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By R. L. Curfman

From January 1, 1965 through July 5, 1970, the very difficult potash ore body of Texasgulf Inc. near Moab, Utah was mined by conventional methods. The mine was gassy, the temperature was high and structural conditions precluded a satisfactory or economical extraction ratio due to the undulating configuration of the ore horizon. In 1966, 67, and 68, alternative mining methods were considered, among which was solution mining of the ore body. Cost studies indicated that the use of crystallizers to evaporate the large amounts of water attendant to solution mining offered no chance of economic success. In 1969 additional testwork and cost studies were carried out utilizing solar evaporation. These studies showed economic potential and justified additional investigation. As a result of these studies, Texasgulf now gathers potash solids from these solar evaporation ponds, (Fig. l), after pumping them from the underground mine as brine. The investigations were concentrated in four basic areas : (1) area evaporation rates and crystal growth habits; (2) underground solution tests including heat transfer rates; (3) accelerated evaporation tests to provide material for metallurgical testing, and (4) tests of evaporation pond lining materials and application techniques, along with area surveys to ascertain if sufficient earth was available in the near vicinity to con-

Jan 1, 1974

By Robert F. Shurtz, William J. Verner

Three basic questions must be answered by an engineer performing an economic analysis of a mineral property: (1) How much can the company afford to pay for the property; (2) At what rate should the property be mined; (3) What will be the return on the investment. These questions often defy reasonable analysis, because at the point in time at which they must be answered little may be known about the grade of ore and the reserve tonnage. The purpose of this report is twofold. First, to derive a method of determining purchase price, rate of production and return on investment which is valid under varying conditions of ore grade and tonnage reserve; and, second, to apply this method to the Margay deposit in an attempt to evaluate it as a business enterprise. This is an actual economic analysis of an existing nickel-copper deposit fictitiously named the Margay. It was carried out for a mining corporation and proved to be the determining factor in the subsequent purchase and development of the property. All data referring to costs, quality and quantity of ore, etc., are accurate and truly represented. Prices used are obsolete but the method is not dependent on those variables. Basic assumptions for the analysis are given in Table I, page 71.

Jan 11, 1966

By Volker Ruth

DURING an experimental investigation of the Kirken dall effect in the Ag-Au system, cracks along grain boundaries in connection with a shift of adjoining crys tallites are observed on the gold-rich side of the couple. Also on the gold-rich side the formation of a zone of small protrusions is found.' The growth law of the width of this zone indicates that the protrusion formation is a secondary effect of diffusion. The protrusions are not found within a distance of approximately 60 from a grain boundary. Unaffected regions along grain boundaries were also observed by Doherty and Davis during precipitation of vacancies in aluminum2 and by Wyon and Lacombe during precipitation of iron in aluminum.3 Thus we may suppose that we have an effect analogous to precipitation in which the crystal tends to maintain its equilibrium vacancy concentration by transporting excess atoms to the surface. At an early stage (i.e., before sintering has influenced the shape of the protrusions) the protrusions have similar shapes (three sided pyramids and roof shapes) and similar orientations within a single grain but vary from one grain to another. Further experiments were carried out on cylindrical Au-Ag single crystal couples. During the weld-

Jan 1, 1963

Assaying, mineralogy, and geology appear in ancient records as early as mathematics, physics, and chemistry. Agricola was the first author to unify the earth sciences, the mineral extractive industries and the mineral processing industries. His text, De Re Metallica, published in Latin in 1556, is recognized as the first technical literature. In 1702 mining instruction was started at Freiberg, Germany. The purpose of this school was to train skilled workers, a program corresponding to present-day, on-job, vocational-technical, upgrading extension training. Formal instruction in mining engineering began at Schemnitz, Hungary, in 1763, at Freiberg, Germany, in 1766, and at St. Petersburg, Russia, in 1773. It is interesting to note that these three schools initiated instruction in mining engineering before formal instruction in civil engineering began at Paris, France, in 1775. Early mining engineering, 1763-1900, was expected to cover all eventualities in the mineral industries. Optional curricula were offered early in the 20th Century but did not reach into all branches until after World War I. Specialization crystallized during World War II under three organic units: (1) Earth Sciences; (2) Mineral Engineering; (3) Mineral Technology, the three together constituting the mineral arts and sciences of the modern world (Fig. 10).

Jan 1, 1950

By T. D. Tiemann

Extraction of silica from the taconites of the Wisconsin Gogebic range by high temperature digestion in caustic solutions has been described.1,2 The ores consist essentially of hematite, goethite, and microcrystalline quartz, detailed descriptions of which appear in the literature.1,3 It is the purpose of this communication to describe some results obtained from a laboratory investigation of an alternative method, that of sintering the ore with sodium carbonate followed by water extraction of the sodium silicate produced. This is analogous to the Deville-Péchiney4,5 soda ash sinter process for the production of alumina from bauxites in which soluble sodium aluminates are formed. Raw mixes of the desired composition were prepared from 10.0 g minus 200 mesh samples of taconite and sintered in nickel crucibles in a muffle furnace controlled to within ±10°F of the operating temperatures. The resulting sinters were pulverized and then leached in distilled water with continuous agitation for 30 minutes at 95°C. The suspensions were vacuum filtered and the residues dried, ignited and weighed. Iron assays on the ignited samples were made by the standard dichromate procedure after dissolution in hydrochloric acid. The percentage of extraction was calculated from the iron assays by the relation:

Jan 1, 1964

By R. I. Jaffee, E. S. Bartlett, D. N. Williams

The oxidation resistance and fabricability of molybdenum powder-metallurgy alloys containing up to 20 wt pct nickel in the form of a fine dispersion were studied. The effects of dispersion distribution and of amount and type (pure nickel or nickel compounds) of additive were considered. A definite improvement in oxidation resistance was observed, but the amount of improvement fell far short of requirements for an oxidation-resistant alloy. Fabricability by hot-rolling was limited. INVESTIGATIONS at Ohio State university1 and Battelle Memorial institute2 have indicated that the attainment of a truly oxidation-resistant molybdenum-base alloy for high-temperature service, with the coincident retention of high-temperature strength and toughness, will be a difficult, if not impossible, feat. Among the most promising alloy systems studied was the molybdenum-nickel system shown in Fig. 1. Alloys in this system show good oxidation resistance at temperatures well above the normal melting point of molybdenum trioxide because of the regenerative formation of protective nickel-molyb-date (NiMoO4) on the surface of the alloy during exposure at high temperatures. Unfortunately, the required alloy content to obtain oxidation resistant molybdenum-nickel alloys far exceeds the limits of the narrow terminal solid-solution boundary, and closely approaches the peri-tectic composition involving the brittle intermetal-lic compound, MoNi. Because of the peritectic reaction, fusion alloys are characteristically brittle, since the MoNi phase, being the last to form, tends to occur as a continuous grain-boundary network around each molybdenum grain. An added problem with this system is that the protective nickel-molybdate layer formed at high temperatures is unstable, undergoing one or more allotropic modifications upon cooling. The volume changes associated with this modification during cooling are such as to cause violent expulsion of the protective molybdate coating from the surface of the piece. This is, of course, quite detrimental in material exposed to cyclic temperature during service. The research reported here resulted from an attempt to overcome the aforementioned problems associated with the molybdenum-nickel alloys primarily by controlling the amount, size, and location of the MoNi phase. By using powder-metallurgy techniques of alloy preparation and sintering the blended molybdenum-nickel powder mixtures at a temperature below the peritectic reaction temperature, molybdenum-nickel alloys with a randomly dispersed MoNi phase were produced. MATERIALS The molybdenum powder used in the preparation of alloys for this study was commercial hydrogen reduced, minus 325-mesh (Tyler) material. Master alloys, by which nickel was added, consisted of elemental carbonyl nickel powder (12 average particle size), an alloy of 50 wt pct Ni-50 wt pct Cr, and compounds of MoNi, Ni,Si, and Ni2B. The nickel-chromium powder was prepared by filing a vacuum-arc-melted ingot, separating impurities magnetically, and screening to minus 200-mesh. The MoNi powder was prepared by pulverizing a hydrogen-sintered powder-metallurgy compact to minus 325-mesh material. Further sizing of this powder for study of effects of dispersion distribution was accomplished by air classification of the minus 325-mesh powder. The Ni2Si and Ni2B powders were prepared by crushing vacuum-sintered powder-metallurgy compacts to minus 200-mesh material. EXPERIMENTAL PROCEDURE Specimen Preparation—The general procedure followed in the preparation of alloys for testing is described as follows: 1) Blending. Either hand-blending of the powders in a ceramic mortar and pestle for X 1/2 or mechanical blending was used. Hand-blending seemed preferable for optimum homogeneity. 2) Compacting. Most of the blended powders were pressed to green compacts at pressures of 15 tons per sq in. in a single-action die, although some were pressed at 80 tons per sq in. A 1 X 11/4 X 1/4-in. green compact was the standard size for oxidation test material, and 7 X 1/2 X 1/4-in. compacts were used for fabricability test specimens. 3) Sintering. All green compacts were sinteredat

Jan 1, 1959

By R. J. Wasilewski

The variation of elastic modulus with terrzperature between -150° and 600°C has been investigated. Compounds close to equiatomic cornposition exhibit very low modulus values and very high damping near room temperature. The modulus rises steeply with both decreasing and increasing temperature. The modulus minimum and the high damping are believed to be connected with a martensitic transformation of TiNi. In bulk material this transition takes place slightly above room temperature quite rapidly and reversibly, with a hysteresis of some 30°C, depending on the Ti:Ni ratio. Oxygen impurity affects the reaction time. THE inter metallic compound TiNi has been reported to exist in an ordered CsCl (B2) structure,l-6 the homogeneity range varying rather markedly with temperature.7 Some investigators reported this compound to decompose peritectoidally to Ti2Ni and TiNi, between 650° and 800°C,3 or below,',g the latter workers also suggesting the decomposition to be strain-sensitive. Purdy and Parr were the first to report a structural transformation to a new, possibly hexagonal, structure at 36°C,7 a temperature indubitably too low to allow the significant amount of diffusion necessary for a peritectoid reaction. Mechanical-property investigations of compositions close to TiNi just above room temperature have qualitatively shown remarkable anomalies, particularly with respect to clamping,' and to a "memory" effect, that is, plastically deformed material returning to its original shape on being heated through the "decomposition" temperature.9 The original explanation of this effect—based on the apparent experimental observation of Ti2Ni or TiNi, formation in the material subjected to tensile or compressive stresses, respectivelp—does not appear plausible. It appeared more probable that the change involved may be a martensitic, diffusionless structural transformation, similar to those observed in other B2 structures such as 0 brass,'' AuCd,ll and AuZn.12 The existence of such transformation has been established recently,', although the symmetry of the low-temperature structure is not yet known. The present paper describes the elastic modulus and damping behavior of polycrystalline TiNi in both structures. EXPERIMENTAL METHOD 1) Specimens. All the specimens to be investigated were prepared from premelted electrolytic nickel and iodide titanium by nonconsumable arc melting and casting in a water-cooled copper mold. The cast billets were canned in mild steel, extruded, and swaged to approximately 0.375 in. diam. The cans were then removed by pickling or machining. Preliminary material balance checks indicated no significant weight losses on melting (less than 5 mg on a 50-g button); hence nominal compositions have been used throughout. In agreement with previously reported observations7 no single-phase material was obtained at—or close to—Ti 1.00 Ni1.00 a small amount of finely divided second phase always being present. It was found that most of the oxygen impurity was associated with this minor phase, which was identified as oxygen-bearing Ti2Ni—possibly Ti,Ni,O. The amount of this phase—at any given Ti:Ni composi-

Jan 1, 1965

J. W. Tomlison—It seems probable that the author's conclusion, that the conductivity of the slags decreases with increasing content of FeO, is erroneous due to the method of plotting the data. Thus, the results of other workers2,3,13,15 show that the conductivity of molten oxide slags increase with increasing temperature, indicating that the trend of the curve shown by the authors is due to the fact that the data for the slags containing relatively small amounts of FeO are at higher temperatures than those for the slags containing relatively large amounts of this oxide. In this connection the work of Wejnarth2 may be mentioned in which in an investigation of a series of iron silicate slags, the conductivity was found to increase with increasing content of FeO; the fact that the author's slags contained TiO2 probably does not affect the issue since it has been shown15,16 that, at least as far as conductivity is concerned, this oxide behaves essentially the same as silica and that mixtures of the oxide with silica have a very low conductivity of the order of 10-4 mhos at 1750°C. In connection with the experimental technique it may be noted that bubbles of carbon monoxide would probably be produced at the surface of the graphite electrodes in contact with the melts thus rendering the accuracy of the measurements somewhat open to question. J. L. Wyatt (author's reply)—Dr. Tomlinson makes reference to works by Martin and Derge, which indicate that slag systems containing no TiO2 are characterized by an increase in conductivity with an increase in temperature. Further, I have cited his examples, which indicate a drastic increase with small temperature change. The results of Dr. Derge's work have no bearing whatsoever on the results of this paper, since the slags under study here contained up to 70 pct TiO2 One cannot generalize on slag systems as a whole on the basis of any one family, for there are definite compounds of ionic nature formed in each system, and the ionic mobilization of these is something that cannot be determined without actual experimentation. Dr. Tomlinson makes reference to an unpublished work which, he claims, shows that titanium dioxide behaves the same as silica in regard to conductivity. Since I have not had 'an opportunity to see the paper I cannot make any comments, but unless the same slag system was studied there can be no specific comparison of results. If the decrease in conductivity of the slag was due entirely to temperature phenomena, as Dr. Tomlinson indicates, then one is without an explanation of the values shown in the paper for slags containing from 10 to 20 pct FeO. I cannot agree that the deviation in findings was appreciably related to temperature change; further, I believe this point was completely covered in the paper. References 13 Endell and Hellbrügge: Glasstech. Ber. (1942) 20, 277. 14 Bockris, Kitchener, Ignatowicz and Tomlinson: Faraday Society. Discussion (1948) 4, 265. 15 Tomlinson: Thesis, London 1949. 10 Bockris, Kitchener, Ignatowicz, and Tomlinson: Unpublished work.

Jan 1, 1951

By Richard D. Call

In any open pit, some slope instability can be expected, varying from bench sloughing to large-scale slope movement. Major slope displacements are preceded by small, but measurable, displacements and by other indicators of instability, such as tension cracks, rock noise, and changes in groundwater levels. A comprehensive monitoring pro- gram, capable of measuring and assimilating displacement related data, is essential for sound pit operation. The objectives of a pit slope monitoring program are 1) to maintain safe operational procedures for the protection of personnel and equipment; 2) to provide advance notice of instability so that mine plans can be modified to minimize the impact of slope displacement; and 3) to provide geotechnical information for analyzing the slope failure mechanism, for designing appropriate remedial measures, and for conducting future re-design of the slope. Surface displacement measurement using conventional survey equipment and extensometers has been the most widely used method, and it is still the most cost-effective. Tiltmeters and borehole inclinometers are also useful tools, and there are promising developments in micro- seismic monitoring. A monitoring system should have redundancy in both type and number of measurements, and be capable of rapid and effective dissemination of displacement information to those affected.

Jan 1, 1983

By J. Chipman, N. J. Grant, E. C. Roberts

An equilibrium study was made of the distribution of chromium and oxygen between liquid iron, containing less than 1 pct Cr, and simple slags of the CaO(MgO)-Si02-FeO-Cr& type in the temperature range 1526' to 1734OC. The effects of slag oxidation, temperature, and basicity were observed. IN spite of the fact that chromium is one of the most important alloying elements in steel, and exists in almost all steels as a significant residual element, little research has been done to determine its behavior in basic steelmaking processes. Considerably more work has been done under silica-saturated acid slag conditions. Korber and Oelsen,' Herasymenko,' and others have generally agreed that in acid steelmaking practice the chromium in the slag behaved as if it were present as the chrom-ous ion (CrO). Work by Hilty- ir, high chromium slags also indicated that chromium may exist as CrO. In basic slag systems no equilibrium data exist. Based on individual studies of basic open hearth and electric furnace practice, Bardenheuer," Rock-rohr,% nd HauckQ oncluded that: 1—chromium recovery increased with decreasing basicity, and 2— chromium recovery increased with increasing temperature, although the effect was small. In similar studies Yavioskii and Dzemyen' concluded that: 1— slag FeO is the most important variable, 2—the basicity of the slag has no effect on chromium recovery, and 3—slag viscosity is not high even when 20 pct Cr,O, is present. Lapitskii\ oncluded that chromium recovery improved as the basicity of the slag decreased and increased with increasing manganese in the metal. Regarding the effectiveness of CrZ08 as a base or acid in basic slags, both Kristofferseno and Trojer" reported that Cr,08 was an acidic component requiring neutralization as 2CaO-Cr,O,. Experimental Procedure The experimental apparatus and procedure used for the present research were similar in most details to those used by Winkler and Chipman" and were described in detail by them. A magnesia crucible was used, holding 60 to 80 lb of Armco iron which was decarburized with hydrogen to about 0.010 pct C. Since all the metal samples solidified without gas evolution, this carbon level was assumed not to be significant. Synthetic slags made by mixing pure oxides were used throughout the study. Temperatures were measured by means of calibrated W-Mo thermocouples and were checked by Pt-Pt-Rh thermocouples. The range of temperatures covered in this study was from 1526" to 1734°C. The chromium content of the iron was in the range 0.032 to 0.82 pct, although the bulk of the tests showed 0.04 to 0.2 pct. The slags were of the CaO(MgO)-SiO,-FeO-Cr,O, type in which the Cr,O, content was from about 2 to 20 pct, although most of the slags showed from about 2 to 10 pct. The FeO range was from about 10 to 65 pct. CaO and SiO, were in the range of about 5 to 45 pct each, yielding a rather wide range of basicity values. The first 12 heats were made without a sulphur addition, and with only 30 min allowed for slag-metal equilibrium to be reached. In previous research it had been shown that less than 30 min was adequate to achieve equilibrium in slags free of Cr2O8.11,14.15 A study of the present data indicated that some of the tests may not have reached equilibrium in this time; accordingly four additional heats were made in which at least 1 hr was permitted for equilibrium to be reached. For reaching

Jan 1, 1955

By George Burgess

NOTE BY THE EDITOR.-This resume of a Technologic Paper which is published in full by the U. S. Bureau of Standards, is brought before the membership of the Institute with the object of affording an opportunity for the open discussion of results of an investigation by the authors named above, of some phases of the manufacture of steel rails which are of great importance to manufacturer and consumer alike. This resume will be presented at the Pittsburg Meeting of the Institute. Discussion is invited, by either members or non-members of the Institute. The discussion may be sent in writing to the Editor, in advance of the meeting, or should preferably be presented in person at the meeting. To those who desire to discuss, copy of the full Technologic Paper (No. 38), as published by the Bureau of Stanaards, will be sent upon request addressed either to the Bureau of Standards, Washington, D. C., or to the Editor, American Institute of Mining Engineers, 29 West 39th Street, New York, N. Y. Summary of Researches and Conclusions The main objects of this investigation were to determine, from measurements taken at representative rail mills, the present American practice regarding the temperatures at which rails are rolled; to demonstrate the ease and accuracy with which such temperatures may be measured, without interfering in any way with the manufacture of the product; to find out what the "shrinkage clause" in rail specifications really means; and, finally, to determine some of the physical properties of rail steels, particularly those of interest in manufacture, some of which seem to be insufficiently known as yet. 1. Ingot Temperatures.-Measurements made in four mills show that ingots for rails are rolled at temperatures ranging from 1,075° to 1,150° C. (1,965° to 2,100° F.), and that, in a series of 20 to 40 ingots, the variation in temperature from one ingot to another is only 10° to 20° C. 2. Finishing Temperatures.-Rails are finished at temperatures ranging broadly from 880° to-1,050° C. (1,615 to 1,922° F.), but usually ranging within 50° C. of 935° C., and occasionally above 1,100° C.

Jan 9, 1914

By J. H. Swisher

HIGH-temperature anneals in wet hydrogen are widely used in research as a technique for decarburiz-ing Fe-C alloys. This technique is also used commercially in processing low-carbon steels for magnetic applications. The results of some calculations to be presented show that for temperatures up to 1100°C there is a critical temperature for maximizing the decarburization rate of alloys containing about 0.1 pct C. The low-temperature portion of the iron side of the Fe-C phase diagram1 is reproduced in Fig. 1. Preliminary calculations show that the critical temperature is between 727" and 905°C. In this range, the alloy contains two phases during heat treatment, ferrite and austenite. Decarburization therefore occurs by a process termed "diffusion accompanied by a phase change".' For intermediate stages of decarburization, the carbon concentration profile in a flat plate is shown in Fig. 2. The carbon content increases linearly from zero at the surface to a value, cB , at the two-phase boundary. cB is known from the phase diagram, see Fig. 1. At the interface where x = 5, the carbon content increases to ci, the initial concentration in the alloy. smith3 has derived an equation which describes the rate of movement of the boundary. With a rearrange-

Jan 1, 1969

By B. L. Averba

THE determination of retained austenite by X-ray diffraction uses the following relationship:"" Pa = constant . RVaA (8) [1] where: P is the diffracted power from phase a; R, the calculated intensity factor; A, the absorption correction; 8, the diffraction angle; and Va, the irradiated volume of phase a For a flat sample making a glancing angle + with the incident beam the absorption correction is calculated as: * 1 sin (28 - 4) A .= 1 [2] µ sin, (28 — 4) + sin 4 where µ is the linear absorption coefficient. Beu3 has proposed that the computed absorption correction be combined with the constant and that the experimental observation of the absorption correction used in the original method be eliminated. This procedure is permissible only if: 1—There is no preferred orientation in the sample, and 2—The geometric requirements have been met precisely. If these conditions are not met the validity of the determination is questionable. Unfortunately the necessary conditions must be tested experimentally for each determination, and this is done most easily by observing whether the apparent absorption has the form of Eq. 2. In practice it may be convenient to plot P/R vs the parameter sin (2? — )[sin (28 — +) + sin +] to obtain straight lines for the ap- parent absorption correction. Deviations from straight lines indicate either that the sample has not been positioned correctly or that the relative intensities are incorrect. Geiger counter spectrometer methods also have been used successfully for retained austenite determinations. In the usual spectrometer arrangement the sample makes equal angles with the incident and diffracted beams (8 = ); thus the absorption correction is simply 1/2µ and independent of 8. The retained austenite is then easily calculated from integrated intensity measurements on austenite and martensite lines. If the austenite content is not too low and if excessive fluorescence is not encountered it is possible to use filtered radiation and a recording spectrometer. The integrated intensities are then proportional to the areas of the diffraction peaks. For lower austenite contents the following technique was used: A bent quartz monochromator and a Geiger counter spectrometer are employed. The monochromatic radiation is focused on the front slit, and the counter slit is made broad enough to include the entire line. A series of readings are taken in the vicinity of the diffraction peak. The highest reading includes the diffraction line plus background. The background is obtained from the average of several readings on each side of the peak. The integrated intensity is obtained by subtraction. CrK, and FeKa have been used for such determinations. This technique has been found to be as sensitive and as accurate as the photographic methods. In the spectrometer methods the ratio austenite/ martensite may be obtained from readings on austenite and martensite lines and the application of Eq. 1. It is also possible to use external standards and to obtain the austenite contents from measurements on the austenite lines alone. The small correction for carbides then becomes unnecessary. The best standards are probably samples with known

Jan 1, 1954

I. PRESIDING OFFICERS. At all Business meetings of the Institute the President, or, in his absence, the Vice-President, or, in the absence of both of them, any other member of the Board of Directors to be chosen by the meeting, shall preside. At all other meetings of the Institute the President of the Council or, in his absence, one of the Vice-Presidents, if present, shall preside II. ORDER OF BUSINESS. At each Business meeting of the Institute the order of business shall be as follows 1. Reading of minutes of preceding meeting. 2 Report of the President. 3. Report of the Treasurer. 4. Report of the Secretary. 5. Election of Directors. 6. Election of Members of the Council. 7. Reports of Standing Committees. 8. Reports of Special Committees. 9. Special Orders 10. Miscellaneous business. This order of business may be changed by a vote of a majority of the Members and Associates present in person or by proxy. The usual parliamentary rules shall govern all meetings of the Institute except in cases otherwise provided by the Constitution or the By-Laws. At all sessions of the Institute other than business meetings, the order of proceedings and the time of adjournment, shall rest in the discretion of the presiding officer

Jan 1, 1923

By C. Feng, P. Levesque

HE addition of rhenium to molybdenum is known to produce alloys with good workability.&apos; Lawley and Maddin found that the critical stress for twinning in this system was lowered by the addition of 35 pct Re, which suggests that twinning may re- place the usual slip operation as the major element of deformation. The twinning elements in bcc Mo-Re alloys have been reported as the (112) planes and the <111> directions.3 This note represents the continuation of this investigation, in which the authors found that the occurrence of twinning promotes the formation of a bcc tetragonal phase, previously identified as u by Greenfield and Beck.4 Specimens of Mo-35 pct Re alloy, prepared as described previusly, were solution annealed at 2400o, cooled to room temperature, and plastically deformed by compression to induce twinning. After subsequent aging for 8 hr at 1300°C, traces of a were observed along the grain boundaries and at the interfaces between the twins and the matrix, Fig. 1. With increased aging time the cr phase grew into larger clusters and finally occupied the entire twinned area, Fig. 2. Experiments also indicated that if twinning did not precede aging, there was no visible evidence of a in the microstructure.

Jan 1, 1962

I PRESIDING OFFICER At all business meetings of the Institute the President, or, in his absence, the First Vice-President, or, in the absence of both of them, any other Vice¬ President or Director, chosen by the meeting, shall preside At all other meetings of the Institute the President, or, in his absence, one of the Vice-presidents shall preside If none of these be present the meeting shall elect a Chairman The President shall do and perform such other duties as may from time to time be assigned to him by resolution of the Board of Directors of the Institute II ORDER OF BUSINESS At each business meeting of the Institute the order of business shall be as follows 1 Reading of minutes of preceding meeting 2 Report of the President 3 Report of the Treasurer 4 Report of the Secretary 5 Election of Directors 6 Reports of Standing Committees 7 Reports of Special Committees 8 Special Orders 9 Miscellaneous business This order of business may be changed at any meeting, by a vote of a majority of the Members and Associates present At all sessions of the Institute, other than business meetings, the order of proceedings and the time of adjournment shall rest in the discretion of the presiding officer

Jan 1, 1923

By Ralph Hultgren

A CONSIDERABLE interest in the subject of superlattices has been mani-fested by many papers and reviews that have recently appeared, both in physical and metallurgical publications. This interest is due largely to the apparent simplicity of the ordering process, which permits the explana-tion of many phenomena on the basis of elementary theory. Moreover, ordering may cause important changes in the physical properties of alloys. In this paper, we shall discuss the causes of superlattices in terms of simple properties of the elements that give rise to them, together with a series of experiments performed to test our conclusions. Evidence is presented that in some cases the process of ordering is more complex than might be supposed. While the different species of atoms are usually found in random posi-tions in alloy lattices, in some cases unlike atoms tend to be nearest neighbors. Bethe&apos;st "order of neighbors" is a statistical measure of this tendency. At suitable compositions it is possible for atoms in large regions to be regularly arranged, which causes superlattice lines to appear in X-ray diffraction patterns. Bragg and Williams2 have dealt with this "long-distance order" in their fundamental work on superlattices. Excellent discussions of superlattices are to be found in current reviews.3,4

Jan 1, 1939

By C. Schlumberger

LAST year the authors presented a paper that discussed the various electrical measurements they perform in drill holes, which they name "electrical coring."&apos; The object of the present paper is to give a brief account of the points of scientific interest that have been elucidated by further field work and laboratory research, as well as the economic, results that have been attained recently. The practical examples given in this paper are drawn, for the most part, from the field work performed in Russian oil fields during the years 1931 and 1932. This is due to the fact that, thanks to the comprehensive cooperation of the Russian geologists and scientists, the authors are allowed to make public a large amount of recent information. In other countries in which the authors are engaged in similar work, the competi¬tion between private companies makes it imperative, for a considerable lapse of time, to avoid publication of the results obtained. The following points will be discussed successively, under sepa-rate headings: 1. Electrochemical phenomena in drill holes. 2. Stratigraphic correlations and tectonic studies. 3. Relations between the productivity of oil horizons and their electrical resistivity. 4. Location of coal seams. 5. Summary and conclusions.

Jan 1, 1933

By A. L. Field

Previous Publications THE first report on the slag viscosity work of the Bureau of Mines was made by one of the authors 1 in 1916. It was concerned chiefly with, the method of measurement. A paper 2 on this phase of the work was presented to the Institute in February, 1917, and a similar paper 3 was communicated to the Faraday Society. Purpose and Scope of the Slag Viscosity Tables Following the development of a suitable method, the next step in the investigation was the measurement of slag viscosity over a wide range of temperature and composition, and the arrangement of this experimental data in the form of tables for the use of the blast-furnace operator. It is believed that this information, if used intelligently, should help the operator to reduce losses in production caused by off-grade pig iron, to improve fuel economy, to promote operating efficiency, and to extend present-day practice to meet the increasing need of smelting lean and complex ores. In the experimental part of the work it was early observed that the temperature-viscosity relations of a slag were determined, for practical purposes, by the relative proportions of the three major constituents, lime (CaO), alumina (Al203), and silica (Si02), provided the percentage

Jan 12, 1917

By Earle E. Schumacher, W. C. Ellis

For the purpose of developing combinations of higher strength and conductivity than are obtainable by heat treatment alone in the age-hardening copper alloys, an investigation has been made of the effects of combinations of heat treatment and strain hardening on the properties in question. The investigation was limited to a study of the alloys containing nickel and silicon; nickel, silicon and cadmium; and cobalt and silicon. The experiments made in the course of the study arc described in this paper in three groups: 1. The effect of hard drawing subsequent to heat trcatment on the mechanical and electrical properties of the alloys. 2. The effect of low-temperature aging on the properties of heat-treat,ed and hard-drawn alloys. 3. The effect of strain on the rate of aging of quenched nickel-silicon-copper alloys. Preparation and Compositions or the Alloys The alloys were prepared by melting cathode copper in an electric resistance furnace and adding sufficient of the hardening elements to bring the compositions to the desired values. The purities of the hardening elements were as high as could be obtained in commercial practice. The metals were what are designated in the trade as electrolytic nickel, cobalt rondelles, commercial stick cadmium and fused silicon. The alloys

Jan 1, 1931