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By Frederick N. Rhines, Robert F. Mehl

It has been shown elsewhere1 that the data on the rates of diffusion in solid metals are fragmentary and in many cases unacceptable. As a result, relatively little is known concerning the factors determining rates of diffusion and the variations in these rates with temperature. The first form of Fick's law (equation 1 below), in which the diffusion coefficient D is assumed invariant with composition, has been recognized for many years as only an approximation. The differential equation representing the second form of Fick's law (equation 4 below) has only recently been integrated by Matano,2 and unfortunately only in cases where a full diffusion-penetration curve (concentration-distance curve) has been obtained can the Matano solution be applied. The proper analysis of diffusion data is thus confined to the data of Grube and Jedele and of Jedele. 8 These data are essentially for one temperature alone and do not furnish any information on the variation of the activation heat of diffusion, Q, with concentration: no information exists on the variation of Q with concentration within a single solid solution field. 11 Much of the argument concerning the properties of metals that determine D and Q has been drawn from data in which variations of the quantities with concentration are unknown, for these data have been taken from experiments that could not furnish this information. Speculation concerning the properties of metals that may be effective in determining D and Q on the basis of data in which the chosen D and Q values are averages over wide concentration ranges of values at particular concentrations, ranges often of 100 per cent, is likely not to be fruitful.

Jan 1, 1938

By Frederick N. Rhines, Robert F. Mehl

It has been shown elsewhere1 that the data on the rates of diffusion in solid metals are fragmentary and in many cases unacceptable. As a result, relatively little is known concerning the factors determining rates of diffusion and the variations in these rates with temperature. The first form of Fick's law (equation 1 below), in which the diffusion coefficient D is assumed invariant with composition, has been recognized for many years as only an approximation. The differential equation representing the second form of Fick's law (equation 4 below) has only recently been integrated by Matano,2 and unfortunately only in cases where a full diffusion-penetration curve (concentration-distance curve) has been obtained can the Matano solution be applied. The proper analysis of diffusion data is thus confined to the data of Grube and Jedele and of Jedele. 8 These data are essentially for one temperature alone and do not furnish any information on the variation of the activation heat of diffusion, Q, with concentration: no information exists on the variation of Q with concentration within a single solid solution field. 11 Much of the argument concerning the properties of metals that determine D and Q has been drawn from data in which variations of the quantities with concentration are unknown, for these data have been taken from experiments that could not furnish this information. Speculation concerning the properties of metals that may be effective in determining D and Q on the basis of data in which the chosen D and Q values are averages over wide concentration ranges of values at particular concentrations, ranges often of 100 per cent, is likely not to be fruitful.

Jan 1, 1938

By R. F. Hehemann, R. H. Goodenow

Thermal arrest, hot-stage microscopy, and transtnission electron microscopy techniques have been employed to study the transformations in low-carbon iron and Fe-9 pct Ni alloys. In continuous cooling experiments, each alloy transforms at an essentially constant temperature for cooling rates below the critical rate required for martensite formation. However, high-tenzperature transformation in pure iron takes place by a different mechanism than that in the 9 pct Ni alloys. Pure iron exhibits an equi-a a structure with a low and random dislocation density while the 9 pct Ni alloy exhibits a cell or lathlike substructure analogous to that of low-carbon martensite. This same substructure characterizes upper bainite in higher-carbon inaterials. UNTIL relatively recently, diffusionless transformations have been considered to take place by the same mechanism and have been termed mar-tensitic transformations.l-3 The most characteristic feature2 of this mode of transformation is the shape change produced by a shear deformation and growth of the product phase frequently occurs at an extremely high velocity approaching that of an elastic wave.4'5 A different mechanism of diffusionless transformation was recognized first in Cu-Ga and other copper-base alloys.6,7 From the absence of surface tilting in these alloys, it has been concluded that transformation is not accomplished by the cooperative shear displacements that occur in mar-tensitic reactions. Transformation presumably takes place by the rapid movement of an incoherent interface which is capable of propagating across parent grain boundaries. Although the transformation is diffusionless in the macroscopic sense, advancement of these interfaces is accomplished by an atom by atom rearrangement. Transformations of this type therefore require thermal activation and are generally operative only at high temperature. Although requiring short-range diffusion at the interface, propagation still occurs so rapidly that the reaction cannot be suppressed with normal cooling rates.7 The resulting microstructures exhibit large, irregular-shaped regions of the product phase, which are essentially free of crystallographic features. Consequently, these reactions have been termed massive transformations. Transformation by the massive mechanism has been reported to occur in ferrous systems involving pure iron and binary alloys of iron with nickel, chromium, and silicon by Gilbert and owen.' The Fe-Ni system is of special interest in that the massive transformation was observed in alloys with less than 15 pct Ni while alloys having more than about 28 pct Ni transformed by the conventional mar-tensitic mechanism. By employing cooling rates substantially higher than those used by Gilbert and Owen, Swanson and Parr have been able to suppress the massive transformation in alloys with 0 to 10 pct Ni9 and produce martensite as revealed by surface relief. The massive transformation in the alloys having less than 15 pct Ni was identified by the lack of surface relief and an irregular rather than clearly acicular microstructure.' Speich and Swann, using thin-foil electron microscopy, identified three distinctly different structures10 in quenched binary Fe-Ni alloys. From 0 to 4 pct Ni the structure consisted of blocky grains of a with a low and random dislocation density. Alloys with 4 to 25 pct Ni exhibited a cell structure with a high dislocation density; and at greater than 25 pct Ni the structure consisted of internally twinned plates. The structural change at approximately 4 pct Ni suggests that alloys with low nickel content transform by a different mechanism than those with intermediate nickel contents and the transition from the cellular to the internally twinned structures at approximately 25 pct Ni is analogous to the transition from needles to internally twinned plates that occurs over a narrow range of carbon contents in Fe-C martensites.11,12 Conventional bainitic and martensitic modes of austenite decomposition operate in ternary Fe-C-Ni alloys having less than 10 pct Ni. This investigation was conducted in order to explore the conditions under which the massive, bainitic, and martensitic transformations occur and the relationships between these modes of decomposition.

Jan 1, 1965

By Alden B. Greninger

That metallographic structures analogous to the martensite of steel may be found in certain copper-aluminum and copper-tin alloys has been known for many years; similar structures recently were found in certain copper-zinc a1loys.l In all three of these alloy systems the martensite structures result from transformation of the metastable fi phase when the speed of cooling from the B range is sufficiently high to suppress decomposition into equilibrium phases. In the normal decomposition of solid solutions into equilibrium phases, diffusion is needed to bring about the necessary changes in concentration, and the rate of reaction falls almost to zero at temperatures slightly above room temperature. The rates of reaction for martensite processes, however, are not dependent upon temperature; the transformation does not require rendjustments of concentration. For example, the martensite transformation in 60:40 (B) copper-zinc does not begin until the temperature has dropped to about minus 30" C., and then continues down to minus 130" C. and probably even at lower temperatures.' Furthermore, martensite processes apparently proceed only while the tempcrature is falling, within the proper range, and cease completely while the temperature is held constant ;$ and they cannot be suppressed by extremely rapid cooling although the rate of cooling for some alloys may be increased to over 10,000 times the critical cooling velocity. Isaitschew, Kaminsky and Kurdjumow2 account for these observed behaviors of rnartensite processes by postulating that the mechanism 6I... consists in a regular rearrangement of the lattice in such a way

Jan 1, 1939

By Alden B. Greninger

That metallographic structures analogous to the martensite of steel may be found in certain copper-aluminum and copper-tin alloys has been known for many years; similar structures recently were found in certain copper-zinc a1loys.l In all three of these alloy systems the martensite structures result from transformation of the metastable fi phase when the speed of cooling from the B range is sufficiently high to suppress decomposition into equilibrium phases. In the normal decomposition of solid solutions into equilibrium phases, diffusion is needed to bring about the necessary changes in concentration, and the rate of reaction falls almost to zero at temperatures slightly above room temperature. The rates of reaction for martensite processes, however, are not dependent upon temperature; the transformation does not require rendjustments of concentration. For example, the martensite transformation in 60:40 (B) copper-zinc does not begin until the temperature has dropped to about minus 30" C., and then continues down to minus 130" C. and probably even at lower temperatures.' Furthermore, martensite processes apparently proceed only while the tempcrature is falling, within the proper range, and cease completely while the temperature is held constant ;$ and they cannot be suppressed by extremely rapid cooling although the rate of cooling for some alloys may be increased to over 10,000 times the critical cooling velocity. Isaitschew, Kaminsky and Kurdjumow2 account for these observed behaviors of rnartensite processes by postulating that the mechanism 6I... consists in a regular rearrangement of the lattice in such a way

Jan 1, 1939

By Carl Altstetter, Emmanuel deLamotte

The influence of an external stress and plastic deformation on the allotropic transformation of single crystals of a Co-30.5 pct Ni alloy was investigated. Experimental results were obtained from dilatometry, X-ray diffraction, and optical and electron microscopy. The effects of stresses could be conveniently divided into three stress ranges. In range I, from 0 to about 400 g per sq mm, the specimens exhibited a multi-variant phase change on cooling and a considerable amount of retained cubic phase. In range II, from 400 g per sq mm to the elastic limit, hexagonal regions of a given orientation grew in size and the cubic phase disappeared with increasing stress level. In range III, just above the elastic limit, specimens transformed into hexagonal single crystals. It was found that plastic deformation, not applied stress, was the factor which determined whether a single-crystal product was formed. The observed macroscopic shear directions were mainly (112) on cooling, but the behavior was more complicated on heating under stress. To explain these properties of the phase change, a model based on the nucleation of partial dislocations is proposed. IT is well-known1 that, on heating, hcp cobalt transforms into an fcc arrangement by shearing on close-packed planes. The crystallographic orientation relationship of the phases is as follows: the habit plane is (OOO1)hcp ?{lll}fcc and a (1010)hcp direction is parallel to a (112)fcc direction. The temperature at which the transformation occurs in pure cobalt is around 420.C 1,2This temperature decreases with increasing nickel concentration: and at about 30 pct Ni it reaches room temperature. However, many of the transformation characteristics remain essentially the same, particularly the crystallographic features.495 A convenient way of studying the transformation is to alloy cobalt with nickel, thus avoiding the difficulties of doing experiments at the high temperatures needed to transform pure cobalt. Due to the hysteresis of the transformation it is possible to choose a Co-Ni alloy with an Ms temperature below room temperature and an A, temperature above room temperature. Either structure of such an alloy could then be studied at room temperature, depending on whether it had just been heated or cooled to room temperature. The choice of nickel is further favored by the small difference in lattice parameters between cubic cobalt and nickel and the similarity of their physical, chemical, and electronic properties. Co-Ni alloys are reported to have neither long- nor short-range order.6 The main purpose of this work was to investigate the influence of an external stress on the transformation characteristics of Co-Ni single crystals. It may be expected that slip, twinning, and transformation should have many features in common in cobalt, because the (111) planes of the cubic phase operate as slip planes when plastic deformation by slip occurs, they are the twinning planes, and they are the habit planes for the transformation. Many previous investigators7-&apos;6 have concluded that dislocations must play an important role in the nucleation and propagation of the transformation, just as they do for slip and twinning propagation. An external stress will affect their motion, and a study of its influence should yield further information about the atomic mechanism of transformation. The present work extends that of Gaunt and christian17 and Nelson and Altstette18 in both qualitative and quantitative effects of stress. The basic concept underlying all the present theories of the transformation of cobalt and Co-Ni alloys is the motion of a/6<112> partial dislocations over {1ll} planes of the cubic lattice. The ABCABC... stacking of the close-packed planes of the cubic phase can be changed into the hexagonal ABABAB... stacking by the sweeping of an a/6 <112> partial on every second plane. Twinning, on the other hand, requires a shear of a/6 <112> on each close-packed plane. The reverse transformation can be effected in a similar way by a/3 (1010) dislocations moving over every other basal plane of the hexagonal phase. Transformation theories2, 7- 12,14 differ in the details of the nucleation of the transformation and the propagation of the partial dislocations from plane to plane. EXPERIMENTAL PROCEDURE Nickel and cobalt rods supplied as 99.999 pct pure were induct ion-melted together under a vacuum of about 10-5 torr in a 97 pct alumina crucible. An alloy containing 30.5 pct Ni was found to have the desired transformation range, with an Ms near -10°C and an j4s in the vicinity of +10O°C. The ingots were swaged to &--in. rod and electron beam zone-leveled in a 10-6 torr vacuum. This procedure resulted in 12-in.-long single fcc crystal rods (designated I to VII) from each of which several tensile specimens of identical orientation were made. Chemical analysis of the bar ends indicated no contamination or gross segregation and no micro segregation was seen in electron micro-probe scans. Tensile specimens with a 9/32-in.-sq by 1-in.-long gage section were spark-machined from the rods and then electropolished or chemically polished to remove the machining damage and to provide a flat surface

Jan 1, 1970

By L. G. Huntley

Introduction IN View of the recent advance made in the knowledge of the nature and conditions accompanying the occurrence of oil and gas, and of the recent activity in drilling in Wyoming, Montana, and western Canada, a discussion of the probabilities of obtaining production in such a reservoir as the Dakota sand in general, and in particular districts, is thought by the author to be timely and likely to result in more intelligent operating in certain parts of the territory underlain by this sand. In Canada particularly it is thought that these general considerations have equal if not more significance in a consideration of the oil and gas possibilities of the formations than have the various local conditions.

Jan 6, 1915

By J. D. Sullivan, Chester R. Austin, J. L. Nunes

It is characteristic of most shales and surface clays that a bloated or vesicular structure is produced by burning to a sufficiently high temperature, usually about 150° to 200°F. above the normal maturing temperature used when making common brick of the same material. Early investi-: gators recognized this phenomenon and attributed it to the release or expansion of gases in the vitrified piece. A number of theories have been advanced on the source of the gas and the manner in which it is evolved, but none has been proved conclusively. T. E. Jackson&apos;s1 early theory that bloating was due to oxygen evolved by ferric oxide in forming ferrous oxide or ferrous silicate was never substantiated by - experimental work. Orton2 thought this explanation unlikely, as all clays should bloat at the same temperature, if this were true. He found that clays bloated in the range from IIoo° to 17oo°C. Also, many clays containing iron did not bloat at all, but fused. Orton also stated that oxida- tion of different types of carbon was a source of gas during burning of clay and should be expelled before vitrification was reached. Seger3 said that he had dissolved ferric oxide in glass with no apparent evolution of gas. Matson4 came to the conclusion that ferruginous clays burned &apos; to vitrification in an oxidizing atmosphere did not have the iron in a ferrous form. According to Wilson,= the gases responsible for bloating might be entrapped air, water, sulphur dioxide, carbon monoxide, oxygen, and hydrocarbons. He spoke of two causes of bloating: (I) incomplete oxidation below the vitrification temperature, and (2) decomposition of compounds and evolution of gases above the vitrification temperature. Decomposition of calcium sulphate was given as the principal example of the latter. Bleininger and Montgomery0 stated that if any time after vitrification began the evolution of gaseous matter was rapid enough so that pressure was produced within the clay, bloating was certain to take place, and a vesicular structure would be formed. They recognized that initial structure, rate of heating, kiln atmosphere, and many other variables affected bloating. Work done by the Emergency Fleet Corporation7 indicated that clays suitable for bloating should be high in compounds of metallic oxides, carbon, sulphur, sodium, potassium, or other equivalent compounds, which either act as a flux or give off gas. Orton2 studied the chemical status of the carbon, iron, and sulphur in clays during various stages of burning, using a Huron shale that bloated under oxidizing or reducing conditions. He found that only a small amount of sulphur remained in the clay and that it could be detected only by dissolving the clay in hydrofluoric acid; i.e., the sulphur was in combination with the silica. orton said that this sulphur was probably in the form of iron sulphide dissolved in the glass phase. The iron sulphide was not broken down by heating, but was dissolved in the basic slag or glass,

Jan 1, 1942

By J. D. Sullivan, Chester R. Austin, J. L. Nunes

It is characteristic of most shales and surface clays that a bloated or vesicular structure is produced by burning to a sufficiently high temperature, usually about 150° to 200°F. above the normal maturing temperature used when making common brick of the same material. Early investi-: gators recognized this phenomenon and attributed it to the release or expansion of gases in the vitrified piece. A number of theories have been advanced on the source of the gas and the manner in which it is evolved, but none has been proved conclusively. T. E. Jackson&apos;s1 early theory that bloating was due to oxygen evolved by ferric oxide in forming ferrous oxide or ferrous silicate was never substantiated by - experimental work. Orton2 thought this explanation unlikely, as all clays should bloat at the same temperature, if this were true. He found that clays bloated in the range from IIoo° to 17oo°C. Also, many clays containing iron did not bloat at all, but fused. Orton also stated that oxida- tion of different types of carbon was a source of gas during burning of clay and should be expelled before vitrification was reached. Seger3 said that he had dissolved ferric oxide in glass with no apparent evolution of gas. Matson4 came to the conclusion that ferruginous clays burned &apos; to vitrification in an oxidizing atmosphere did not have the iron in a ferrous form. According to Wilson,= the gases responsible for bloating might be entrapped air, water, sulphur dioxide, carbon monoxide, oxygen, and hydrocarbons. He spoke of two causes of bloating: (I) incomplete oxidation below the vitrification temperature, and (2) decomposition of compounds and evolution of gases above the vitrification temperature. Decomposition of calcium sulphate was given as the principal example of the latter. Bleininger and Montgomery0 stated that if any time after vitrification began the evolution of gaseous matter was rapid enough so that pressure was produced within the clay, bloating was certain to take place, and a vesicular structure would be formed. They recognized that initial structure, rate of heating, kiln atmosphere, and many other variables affected bloating. Work done by the Emergency Fleet Corporation7 indicated that clays suitable for bloating should be high in compounds of metallic oxides, carbon, sulphur, sodium, potassium, or other equivalent compounds, which either act as a flux or give off gas. Orton2 studied the chemical status of the carbon, iron, and sulphur in clays during various stages of burning, using a Huron shale that bloated under oxidizing or reducing conditions. He found that only a small amount of sulphur remained in the clay and that it could be detected only by dissolving the clay in hydrofluoric acid; i.e., the sulphur was in combination with the silica. orton said that this sulphur was probably in the form of iron sulphide dissolved in the glass phase. The iron sulphide was not broken down by heating, but was dissolved in the basic slag or glass,

Jan 1, 1942

By J. G. Thompson

OXYGEN, nitrogen and hydrogen are present in practically all metals in one or more of the following forms: (1) molecular gas in blowholes or blisters, (2) combined in nonmetallic inclusions such as nitrides, oxides or silicates, and (3) in solid solution in the metal. Gaseous elements, in some of these forms, are encountered in practically all metals and alloys but possibly have received most publicity in connection with iron and steel. In fact, the entire steel industry depends upon the control of the oxygen content during the refining process, as well as in the finished material, and it was only after the adoption of the use of efficient deoxidizers such as manganese that the production of good steel with a low carbon content became possible. In normally clean, sound steel the amount of hydrogen is negligible and the amounts of oxygen and nitrogen vary from a few thousandths to a few hundredths per cent. However, many of the effects attributed(27,31,40.41,53,54,55,56,62) ? to the presence of these elements are important and at first glance appear to be out of proportion to the amounts of impurities involved. The presence of oxygen is believed to affect the solubility of carbon in austenite and ferrite and thereby to affect the structure of the iron or steel. Such properties as strength, hardness, ductility, elastic limit, impact resistance, magnetic permeability, tendency toward caustic embrittlement, irregularity in carburization, the cutting life of tools, certain corrosion phenomena, the presence of flakes, seams, bands, ghost lines and hair cracks, and the tendency to age-harden, all have been attributed to the presence of oxygen.

Jan 1, 1932

By Clair Upthegrove, Elbert S. Rowland

THE widespread interest in the alloys of beryllium with copper is due principally to the fact that certain compositions show very favorable precipitation-hardening characteristics and are, in fact, the strongest nonferrous alloys known at the present time. Investigations have been conducted by Masing and Dahl and others on the physical characteristics of ternary beryllium alloys, in an attempt to produce precipitation-hardening effects with a smaller amount of beryllium than that required in the binary copper-beryllium alloys (2.0 to 2.5 per cent Be). The results of these investigations show that ternary alloys of beryllium with Cu-Sn, Cu-Al and Cu-Zn, among others, exhibit promising improvements in physical properties after precipitation-hardening treatment and, while the increases in properties obtained are not as high as those realized from the binary copper-beryllium alloys, excellent properties are: obtained with beryllium contents averaging about one-half the amount required in the binary alloys. This paper presents the results of an investigation of the equilibrium relations of certain alloys containing copper, tin and beryllium. The alpha-phase boundary of the ternary system is given for alloys containing from. 0 to 1 per cent beryllium. The equilibrium conditions beyond the alpha-phase boundary are presented for alloys containing up to 32 per cent tin and 1 per cent beryllium. The data were collected by means of

Jan 1, 1935

By Joseph M. Jacisin

Fatigue tests were conducted on 2017-T4 alumium in alloy in an u1lrcthig.h vacuum of 2 x 10-lo Torr and in air. The vatio of vacuum-to-air faligue life for this ~malerial varied Jrom 3.5:1 at a strain of 2.5 X 1O-3 ill. pegr in. to 8:l at a strum of 3.3 x X ill. per 171. Sotlze pvelivtlinary data were also obtained on the faligue life of the alumirnum alloy in a dvy-nitrogen atmosphere. A dark deposit observed on the fracture surfaces of the aiv-tested specimens was identified as oxides of tr~angarzese and magnesium This observalion, and the close correlalion betaveen results obtained in vaCuum and dry-nitrogen environtments, tend to confirm that air stvongly influences the fatigue mechanism by a covrosion process. THE fatigue life of certain metals is known to increase when the atmospheric pressure is reduced. Gough and Sopwith1-2 postulated that this is due to a joint chemical and mechanical process operating in air at the surface of the metal with oxygen and water vapor playing significant roles. Wadsworth and Hutchings3 observed that aluminum is mainly affected by the presence of water vapor. Very little information is available on the fatigue properties of structural aluminum alloys in a vacuum environment. This report describes work performed on 2017-T4 aluminum alloy in an ultrahigh vacuum (2 x 10-loTorr) and in air. Some preliminary data are also presented on the fatigue life of the alloy in a dry-nitrogen environment. 1) EXPERIMENT 1.1) Test Material. The material tested was commerciaT 2017-T4 aluminum alloy which, in addition to aluminum, has an approximate composition of 4 pct Cu, 1 pct Fe, 0.8 pct Si, 0.5 pct Mg, 0.5 pct Mn, plus smaller amounts of other elements.* Some typical naturally age to a substantially stable condition. Specimens were then machined from these rods and ground to a No. 8 microfinish. In order to minimize variation in material characteristics, specimens were made from rods procured from the same lot. 1.2) Apparatus. The apparatus and test specimen used in the fatigue tests are shown in Fig. 1. The device utilized a single-cantilever beam with rotating-bending loading. Bending stress was applied to the fatigue test specimen by placing a spacer beneath the bearing support, thereby providing a constant deflec-

Jan 1, 1968

By H. A. Bedworth, W. H. Bassett

The amount of oxygen present in refined copper bears an important relation to the effects of various impurities on physical properties of copper, as well as the effects of reducing gases at higher temperatures. It seems fitting at this time, when the effects of reducing gases on copper are being discussed, to describe methods that have proved satisfactory for the determination of oxygen and sulfur, and to present some results obtained by investigation of these methods in the authors&apos; laboratory. The procedure for the determination of sulfur is closely interrelated with that for oxygen and has, therefore, been included. It was first proposed by Hampe1 that oxides in copper could be accurately determined by the loss in weight sustained by finely divided copper when reduced at red heat in pure hydrogen, or by the weight of water produced. Hampe&apos;s method was later modified by Archbutt,2 who established the accuracy of the method and demonstrated that equally accurate results were obtained by noting the loss in weight or by weighing the water formed. The determination of oxygen by heating in carbon monoxide has been proposed by West.3 In our hands this method has given slightly lower results than obtained by heating in hydrogen. Heath4 found that the loss in weight after heating in hydrogen did not represent the true oxygen as cuprous oxide but included also gases derived by the metal from the fuel and refining in the furnace, and any trace of mechanically held moisture. He found, further, that the copper after ignition retained hydrogen equivalent to about 0.01 per cent. Heath proposed to determine the amount of occluded gases by preliminary ignition for 20 min. in pure carbon dioxide—and to correct the error caused by absorbed hydrogen by subsequent ignition and cooling in carbon dioxide, finally replacing this gas with air.

Jan 1, 1926

By R. A. Salathiel, A. D. Kaiser, P. H. Monaghan, B. E. Morgan

The productivities of many hydrocarbon-bearing for-rnntions appear to be reduced during drilling, completing and repairing operations. The reason for these othcarwise unexplainable low productivities may be a drastic reduction of formation permeability immediately surrounding the borehole. A possible cause of the reduced permeability is swelling and dispersion of clays present in porous media when contacted by fresh water or mud filtrates. Hence, the invasion of fresh water or mud filtrate into hydrocarbon-bearing formations that contain clays may cause low productivities as a result of formation damage. Present laboratory investigations have yielded results which supplement existing literature on formation damage. An expanded-type clay, montmorillonite, way found in hydrocarbon-bearing formations not previously analyzed. When sand columns and formation cores containing montmorillonite were contacted by fresh water, their oil permeabilities were reduced. This reduction in oil permeability way restored partially but not completely by a repair procedure, i.e., flooding with kerosene containing organic agents or flooding with water containing electrolytes. Hence, where montmorillonite is present in formations, prevention of formation danzage was indicated to be the only complete solution to the problem. To prevernt formation damage, results suggested use of an approximately 1 per cent solution of calcium chloride or stronger solutions of sodium or potassium chloride. In conventional rotary drilling operations the wall of the hole is exposed to drilling mud for days, weeks, and in some instances for as long as several months. During this time, drilling mud filtrate seeps slowly into formations surrounding the hole. The permeability and stability of many formations, especially those containing clayey materials, are impaired by the mud filtrate. Often interaction between the mud filtrate and the formation causes drilling and production difficulties. Serious reduction in productivity of oil and gas formations during drilling, completing and repairing wells has been noted often in recent years. Cases are known of development wells which produced only small volumes of fluid upon completion. However, after a period had elapsed, they began to produce oil or gas in commercial quantities. In other cases, results of drill-stem tests taken during the drilling of deep wells have indicated good production should be obtained from shallow formations. Later difficulty has been experienced in obtaining production from these shallow formations which had remained in contact with drilling muds for an extended time. In yet other cases wells have failed to attain the productivities expected from previous performance after the use of drilling mud as a circulating fluid during workover operations. It is evident from the field behavior cited that the productivities of certain oil- and gas-bearing formations have been damaged by exposure to drilling muds. This reduction in well productivity, called "formation damage", causes serious consequences. In development wells, expensive remedial operations are incurred. In wildcat wells, good formations may appear to be marginal or even non-productive. The importance of formation damage has been recognized by a number of investigators1-s who have considered the effects of fresh water, saline solutions and aqueous mud filtrates on the permeabilities of formations. A general conclusion from such studies is that interaction between water and formation clays reduces permeability of reservoir rock and that the permeability decreases as salinity of the water decreases. Data in these references, however, concern the permeability change with only a single fluid present. A more pertinent and direct consideration in the production of oil and gas from wells is the permeability change when two fluids, oil and water, are present. Recognizing this, Nowak and Kreuger2 and Bertness1" considered several ways in which mud filtrates and saline solutions caused reductions in the oil permeability of formation cores. Investigations discussed here were designed to supplement information in the literature on changes in oil

By A. E. Gorum, I. Cornet

Fatigrle of ionic crystals has been studied primarily in magnesinm oxide. under cyclic stress dislocations move irrreversibly; they multiply; slip bands form and grow; cracks mucleate and propagnte, and failure occurs. The use of ionic crystals such as MgO is advantageorus in such investigations because they are optically transparent. Individual dislocation Intersections with {100} surfaces may be observed with a standard microscope, using etch-pit techniques. Slip, deformation, crack .formation, and fracture in MgO crystals under cyclic stress are compared with cotrresponditzg processes in metals. ThE effect of cyclic loading in metals has been studied for many years. The appearance of slip lines is readily observed and the ensuing fracture may also be seen. From these observations it is possible to predict the behavior of a material and make an educated guess as to what is happening internally, but the actual changes taking place within the structure are not readily apparent. If one could obtain a material in which the individual glide components could be observed, it would be invaluable in determining the actual slip distribution resulting from cyclic loading as well as the distribution of slip in the neighborhood of a growing crack. Such a material is magnesium oxide. Dislocation arrays may be observed by means of etch pits

Jan 1, 1961

By R. F. Decker, J. R. Mihalisin

Phase transformations in a series of relatively pure nickel-titanium-aluminum binary and ternary alloys were studied. The purpose was to clarify age-hardening mechanisms, especially in predominantly titanium-hardened compositions. The micro-structures, as determined on a tirne-temperature-transformation basis by light and electron microscopy and X-ray diffraction, were correlated with room temperature and hot hardnesses. The stability of the ? phase under nonequilibrium conditions was shown to be important in this system. MANY of the alloys designed for service in the temperature range of 1200oF (649°C) to 1800°F (980°C) are austenitic iron-.nickel base alloys hardened by titanium and aluminum. The control of high-temperature properties of these alloys has been advanced by the knowledge of microstructures provided by the equilibrium diagrams of Taylor and Floyd1 and Taylor.2, 3 However, there have been notable instances in the predominantly titanium-hardened alloys where the correlation of properties with microstructure and the equilibrium diagrams has been unsuccessful. Mihalisin and carrol14 have noted in electron microscope studies of commercial alloys of this type that a fee phase precipitates and transforms to 71 (hep Ni3Ti) in stress-rupture tests. Bieber5 found that this fee phase remained in nickel-chromium-titanium alloys even when aluminum was excluded. Age hardening in iron-nickel base alloys has been attributed to 71 by Craver, Aggen, and Dyrkacz,6 ? (fee phase based on Ni3Al) by Beattie and Hagel7 and both phases by Lena,8 Yet, on the basis of the nickel-titanium-aluminum equilibrium diagram of Taylor and Floyd shown in Fig. 1, it has been difficult to understand the presence of ? in low aluminum alloys. Furthermore, the characteristic coarse dispersion of 71 has not been commensurate with the marked aging response. Also there have been anomalous grain boundary transformations in the iron-nickel base alloys which have markedly reduced notched stress rupture properties.9 These have been related to boron content and residual cold work. Recently, Golubtsova and Mashkovich,10 Buckle and Manene11 and Bogaryatskii and Tyapkin12 have noted a transition fee Ni3Ti in titanium-hardened nickel-base alloys. It was apparent from the latter studies that a transition phase was important in the nickel-titanium-aluminum system. The purpose of this study was to identify this phase, measure its transformation characteristics and kinetics, and attempt to correlate these findings with age hardening. It was believed that time-temperature-transformation studies, because of their adaptability to transition phases, would be of most value for this investigation. Accordingly, this method of study was undertaken on relatively pure nickel-titanium-aluminum alloys with controlled variations in boron content and residual cold work. EXPERIMENTAL PROCEDURES Compositions were selected from the nickel-titanium-aluminum isothermal section of Taylor and Floyd.&apos; These compositions are plotted in Fig. 1 and were selected to obtain equal aging potential of approximately 15 pet by volume of the equilibrium precipitate. The materials were vacuum melted from

Jan 1, 1961

By I. A. Goddard

INTRODUCTION This paper deals with the development of the sublevel open stoping (SLOS) method in lead orebodies at the Isa Mine of Mount Isa Mines Limited, during the last ten years. Open stoping in different forms has been used at the Isa Mine for many years. Prior to the period under review, stopes were small, pillars were not always recovered, and scrapers extracted the ore. By the end of the sixties, the use of load-haul-dump units was becoming more widespread. Wagner ST5&apos;s were the mucking units for the lead cut and fill stopes. Some of the open stopes in 5 orebody above 13 level had 100 kW slushers, but the more southerly stopes were the sites for the introduction of diesel front-end loaders for extraction. In the early seventies, new methods were used in the block of six stopes in 2 and 5 orebodies between 8 level and 13 level and a trial stoping project was undertaken in 7 orebody between 11 level and 13 level to determine possible stope dimensions for the extraction of the Racecourse orebodies below 13 level. By the mid-19701s, stoping was well underway in 5, 7 and 8 orebodies between 13 level and 15 level, using the &apos;triplet&apos; system, incorporating cemented hydraulic fill to allow greater pillar recovery. As the eighties were entered, development of the Racecourse orebodies below 15 level commenced, as did preparations for 1 orebody in the upper levels of the north end of the mine. In both cases, the pillar recovery method has been changed to reduce the amount of cemented fill required for pillar recovery. GEOLOGY Most of the lead orebodies at Isa Mine lie chiefly to the north of the central shaft complex. They are bedded sulphide deposits in a host rock called Urquhart Shale, which dips at roughly 650 to the west. The main minerals are galena and sphalerite, with the silver mineral, freibergite, being contained in the galena. To the hangingwall of the sequence are the Black Star orebodies (1, 2 and 5) which are relatively wide, pyritic and with low to above average grade lead. The Racecourse orebodies (6 to 16) lie to the footwall, and have a large variation in width, low to high grade lead, and gradation in the lead to zinc ratio from north to south. Stope outlines are often determined by economic or engineering considerations rather than geological. The published extraction reserves are 56 million tonnes of primary ore, containing 150 grams of silver per tonne, 6.4% lead and 6.5% zinc. Traditionally, it has been regarded as lead ore, although the dominant revenue earner varies from time to time. In the Black Star orebodies, the ore and hangingwalls are more competent and open stoping has long been used. The major Racecourse orebodies which have been open stoped are 7 and 8 orebodies. This has been where the orebodies are wider (to the south) and where hangingwall conditions allow. This latter aspect has been greatly influenced by the presence of &apos;silica dolomite1. This tough, relatively homogeneous, non-bedded rock is, in fact, the host rock for the copper mineralisation at Mount Isa, and provides a competent hangingwall for some of the lead stopes. While the shale&apos;s bedding and jointing has a major influence on the ground conditions, there is a major fault system which causes local problems. The principal virgin stress direction is perpendicular to the bedding, but the local stress situation is complicated because of shielding by filled stopes in the hangingwall copper orebodies and because of the interaction between orebodies being extracted to the footwall. Most development on strike is mined with a &apos;shanty-back’, with the back being as close to normal to the bedding as possible. This is near parallel to most jointing and the principal stress direction. Figure 1 is a plan view of 14 level north, which provides a representative horizontal section through the orebodies. A typical cross section is shown in Figure 2. The narrow, parallel footwall orebodies can be seen to differ from the wider hangingwall orebodies.

Jan 1, 1981

By C. E Shoenfelt, Gail F. Moulton

Proven and developed oil reserves, and productive capacity increased during 1943 in the fieids of the Rocky Mountain region. Oil production during the year was nearly 45 million barrels, or slightly less than in 1942. The rate of production at the start of 1944 was slightly less than at the start of 1943. Pipe-line projects scheduled for completion during 1944 should permit a substantial increase in the rate of production. Wildcat exploration was more extensive in Montana during 1943 than in other states in the region. The results of wildcat drilling were unsatisfactory, although new oil fields were discovered on the Gebo, Little Buffalo Basin and Steamboat Butte structures of Wyoming, the Gage anticline of Montana, and the Clark Lake structure of Colorado. The area of the structures on which the discovery wells were drilled is known to be considerable, but further drilling is required to determine the importance of these fields. The most important increase in proven reserves resulted from the drilling to newly discovered deeper producing formations in the Elk Basin and other fields of the Big Horn Basin area of northern Wyoming. Lack of a market and unfavorable prices for heavy black oils had prevented complete exploration of favorable areas in the Rocky Mountain region for many years. In particular, the effect on further exploitation of the Big Horn Basin area had been quite serious. The increased demands for all oils created by the war and an increase in price in February 1943, combined later with Government approval of construction of pipe lines from the Big Horn Basin area to the Billings and the Casper districts, provided a basis for undertaking a drilling program. The important additions to reserves were made by drilling in previously discovered fields. The newly discovered fields resulted from drilling on favorable structures which had been known for several years. A continuation of the favorable results obtained during 1943 seems possible only if further testing of the newly discovered fields is satisfactory and if drilling on less favorable known structures or geophysical prospects results in the discovery of new fields. The amount of drilling in the Rocky Mountain states of Colorado, Montana and Wyoming, was about the same during 1943 as .in 1942. However, owing to the fact that a number of wells of large potential production were completed in the Elk Basin field, the total initial production of the prodicing wells was- nearly twice as great for 1943 as for 1942. Explorational activity at the end of 1943 seemed to be directed to geophysical methods, which are required to discover structures hidden beneath the rocks of Tertiary age in the Powder River and other large sedimentary basins. It is in

Jan 1, 1944

By Gail F. Moulton, C. E. Shoenfelt

Proven and developed oil reserves, and productive capacity increased during 1943 in the fieids of the Rocky Mountain region. Oil production during the year was nearly 45 million barrels, or slightly less than in 1942. The rate of production at the start of 1944 was slightly less than at the start of 1943. Pipe-line projects scheduled for completion during 1944 should permit a substantial increase in the rate of production. Wildcat exploration was more extensive in Montana during 1943 than in other states in the region. The results of wildcat drilling were unsatisfactory, although new oil fields were discovered on the Gebo, Little Buffalo Basin and Steamboat Butte structures of Wyoming, the Gage anticline of Montana, and the Clark Lake structure of Colorado. The area of the structures on which the discovery wells were drilled is known to be considerable, but further drilling is required to determine the importance of these fields. The most important increase in proven reserves resulted from the drilling to newly discovered deeper producing formations in the Elk Basin and other fields of the Big Horn Basin area of northern Wyoming. Lack of a market and unfavorable prices for heavy black oils had prevented complete exploration of favorable areas in the Rocky Mountain region for many years. In particular, the effect on further exploitation of the Big Horn Basin area had been quite serious. The increased demands for all oils created by the war and an increase in price in February 1943, combined later with Government approval of construction of pipe lines from the Big Horn Basin area to the Billings and the Casper districts, provided a basis for undertaking a drilling program. The important additions to reserves were made by drilling in previously discovered fields. The newly discovered fields resulted from drilling on favorable structures which had been known for several years. A continuation of the favorable results obtained during 1943 seems possible only if further testing of the newly discovered fields is satisfactory and if drilling on less favorable known structures or geophysical prospects results in the discovery of new fields. The amount of drilling in the Rocky Mountain states of Colorado, Montana and Wyoming, was about the same during 1943 as .in 1942. However, owing to the fact that a number of wells of large potential production were completed in the Elk Basin field, the total initial production of the prodicing wells was- nearly twice as great for 1943 as for 1942. Explorational activity at the end of 1943 seemed to be directed to geophysical methods, which are required to discover structures hidden beneath the rocks of Tertiary age in the Powder River and other large sedimentary basins. It is in

Jan 1, 1944

By T. B. Massalski, C. S. Barett

THAT metals and alloys of the body-centered-cubic structure tend to become unstable at low temperatures is so nearly universal that any exceptions are worthy of special attention. Studies of the exceptions may disclose unrecognized examples of metastability or may shed light on the nature of some of the factors that stabilize the body-centered-cubic phase. Among the structurally analogous body-centered-cubic 3/2 electron compounds, the ß-phase in the Cu-Zn system deserves further attention for, although this phase is known to undergo partial mar-tensitic transformation on cooling below room temperature to the temperature of liquid nitrogen when the composition is less than about 42 wt pct Zn, it does not transform on cooling .when there is more than this amount of zinc present.1-4 The present authors recently found that an alloy containing 48.35 wt pct Zn could be transformed, however, if deformed severely at room temperature or lower temperatures.V his discovery led to the suggestion that the jerky flow of ß-brass single crystals6 and some of the unusual temperature variations of the yield strength and hardness are due to strain-induced transformation during the tensile tests. The present investigation is an extension of that work to cover the entire available range of compositions of Cu-Zn ß-phase alloys and certain interesting compositions of the ß-phase in the Cu-Zn-Ga system. Particular attention is given to the structure of the transformation product resulting from cold work, which is found to vary with alloy composition, and to the temperature range in which transformation can be induced in the various alloys. The composition limits of the body-centered-cubic phase in the Cu-Zn system, based on a recent review by Raynor7 and the precision determinations of Beck and Smith: are shown in Fig. la; in the ß region the alloys are disordered and in the ß region they are ordered. The rate of ordering is so rapid that a high degree of order is found in any of these alloys immediately after quenching. Experimental The nine binary and four ternary alloys of this investigation were prepared from cathode copper (99.99 pct purity), electrolytic zinc (99.99+ pct), and gallium (99.98+ pct). All alloys were cast in transparent Vycor tubing, homogenized at temperatures between 800° and 890°C, and quenched in water. Ternary alloys were cast in small amounts (-5 g) to predetermined compositions to fall along a line of constant electron concentration in the ternary system. Changes of weight during the casting operation of the ternary alloys were not greater than 1 part in 2500 from the intended nominal weights and therefore their compositions were accepted without chemical analyses. All binary alloys were cast in larger amounts (100 to 150 g), homogenized, and hot rolled after preheating to 800°C. The central portion of the rolled strip of each alloy was annealed for eight days and quenched in brine. All binary alloys were analyzed chemically. The compositions, heat treatments, and metallographic appearances of all alloys are tabulated in Table I. Various samples were subjected to heat treatment or cold work at several temperatures and were then examined metallographically or by means of X-rays. Specimens about 6x6x3 mm in size were examined metallographic ally to confirm the presence of the ß-phase after quenching. Cold work was introduced by fastening each sample between two pieces of steel, cooling the assembly to the desired temperature, and transfering it rapidly to a vise where moderate or severe compression was immediately applied. Cold working at liquid helium temperature was done by a chisel-shaped tool mounted on an X-ray spectrometer, described elsewhere.% A!! metal-

Jan 1, 1958