Search Documents

By B. H. Kear

All the possible ways of forming simple two-dislocation boundaries in multiple slip orientations are deduced. It is shown that the principal differences in work hardening behavior of crystals plastically deformed in these orientations can he accounted for in terms of the likelihood of formation of diffuse boundaries, or deformation bands, consisting of the products of dislocation reactions of the Lomer type. Also, it is pointed out that the break-up of boundaries under the applied stress is more likely to yield interstitial jogs than vacancy jogs, whereas glide dislocations cutting throuqh dislocations trapped in particularly stable boundam'es can acquire both types of jogs. USING Frank's' grain boundary formula, Ball and Hirsch2 determined the parameters of all the possible boundaries that can be built from two sets of glide dislocations in the fee structure. This paper deduces the geometrical possibilities for the formation of these two-dislocation boundaries in the different multiple slip orientations, and discusses the role of boundaries in work hardening and in jog formation. Formation of Two-Dislocation Boundaries in Mutiple Slip Orientations. The parameters of the possible two-dislocation boundaries for any crystal orientation can be deduced most conveniently using the boundary formulae due to Amelinckx,3 in conjunction with the stereographic projection shown in Fig. 1. Suppose that slip occurs in a-BC and ß-CA. According to Amelinckx, when the two systems of glide dislocations are parallel, the rotation axis, u, of the boundary is parallel to (a x ß) and the unit normal, u, defining the boundary plane is parallel to (a x ß) x (BC x CA). On the other hand, when the glide dislocations form a crossed grid, u is parallel to (BC x CA) and u is parallel to (a x CA) x (ß x BC). In Fig. 1, (a x ß) is the pole of the great circle passing through a and ß, so that u is parallel to DC, i.e., parallel to [110]. Furthermore, (a x ß) x (BC x CA) is the pole of the great circle passing through DC and 6, so that u is parallel to [110]. Hence, when all the glide dislocations are parallel, the boundary is pure tilt with parameters u = [110], v = [ 110]. Similarly, it may be shown that the corresponding crossed grid of dislocations is a mixed boundary with u = [111], u = [111]. Consider the case of a crystal compressed in the [001] orientation. In this orientation, according to Fig. 1, there are eight available slip systems. In what follows, the different types of two-dislocation boundaries that are possible in this orientation will be examined by taking different combinations of two slip systems out of the available eight, with a-BC always one of the systems. Case (i)—Slip Systems a-BC and d-CB. The formation of a tilt boundary in (101), which consists of a crossed grid of edge dislocations with vectors BC andCB, is illustrated in Fig. 2(a). As the figure shows, slip is required in the system a-BC in one part of the crystal and in d-CB in the other part, with both sets of dislocations entering the boundary from opposite sides. The rotation axis of the boundary lies in (101), depending on the relative densities of the two sets of edge dislocations in the boundary. Case (ii)-Slip Systems a-BC and ß-CA. The two possible boundaries are shown in Figs. 2(b) and (c); boundary (b) is tilt with u = [110], u = [110], and

Jan 1, 1962

By R. A. Deju, R. B. Bhappu

Further information on the surface characteristics of the silicate minerals was obtained by experimentally correlating the oxygen-silicon ratio of the silicates with their electrokinetic properties. Specifically, the behavior of the minerals in an electric field was investigated using zero point of charge as a parameter. A modified electrophoresis cell was used for the determination of electrophoretic mobilities. It was shown that there is an increase in the zero point of charge with increasing oxygen-silicon ratio in the silicates. Finally, a chemical interpretation was presented to describe the surface phenomena observed in the experiments. In recent years great interest in surface chemistry has produced a number of methods to study the surfaces of minerals and to observe the phenomena occurring at their interfaces. One such method is discussed in this paper. A rather complete review of the surface characteristics of the oxide minerals has been undertaken by parks,' but, a similar study has not been made for the silicate minerals. Two previous papers by the authors2'3 attempted to remedy this situation. In these papers it was demonstrated that the reaction between the silicate mineral particles and acidic water involves mainly an exchange of metal ions for hydrogen ions on the surface of the solid, leading to an increase in pH of the aqueous phase. Also, the degree of reaction was found to depend on the oxygen-silicon ratio of the silicate structure, being least for the quartz and greatest for the olivines. A hypothesis was then set forth explaining that upon the fracturing of a silicate mineral, the oxygen-metal bond (which is almost entirely ionic in character) will break more easily than the stronger oxygen-silicon bond. This results in the exposure of unsatisfied oxygen sites on one hand and active, exchangeable cations on the other. These active sites on the fractured surfaces are then available for reaction with the hydrogen ions in acidified aqueous solution. Thus, an increase in degree of adsorption of hydrogen ions occurs as the oxygen-silicon ratio increases due to the presence of a larger number of active sites on such minerals. A correlation between oxygen-silicon ratio and electrokinetic properties will be further pursued in this paper from both the theoretical and experimental points of view. Efforts will then be made to present a chemical interpretation of surface phenomena observed in the experiments. It is believed that this study may supply pertinent information on the behavior of silicate minerals in froth flotation systems. ELECTROKINETIC STUDIES Equipment: In a previous paper,2 Deju and Bhappu described a simple method for determing the zero point of charge using a potential across a cata-phoresis cell and observing particle movement by means of a Rayoscope* optical system. This setup is simple in design and operation and extremely reliable. With care, reproducible results within 1.5% accuracy may be obtained. A new setup has been developed, based partly on the design by Zeta-Meter Corp.4 and partly on previous cells used at the New Mexico Bureau of Mines. This new, modified cell is shown in Fig. 1. Although

Jan 1, 1967

By NILS DANIELSEN

THE name of Swedish charcoal iron will probably bring to the memory of many old consumers an extremely tough and ductile iron which was formerly used in considerable quantities for common blacksmith purposes. To-day very little of this iron goes to such kind of work. Swedish charcoal iron is merely a speciality which is chosen whenever its remark¬able properties can be utilized. By giving a rough sketch of the manufacturing process of Swedish charcoal iron, the character of the iron, its weak as well as its strong points will more easily be understood. Swedish charcoal iron is a wrought iron also known in the United States under the name of Norway iron and Swedish Lancashire iron. The name Norway iron seems to have been attached to the product for the reason that in the earlier days it was generally brought into the States by Norwegian ships. However no iron of this kind is now made in Norway. The reason for the name Swedish Lancashire iron is that the manufac¬turing process emanated from Lancashier in England, the method being generally adopted in Sweden in the years 1831-1850. Today this iron is, with the exception of one plant in the United States, made in no place in the world outside of Sweden.

Jan 1, 1924

By Edwin Ludlow

T HE OPEN FORUM on this subject called by Mr. Hoover at the recent meeting of the Institute' brought out a large number of very able papers, and a very full discussion of all the problems involved. The criticisms of the bituminous industry were: 1. That it was over-developed with the possible output nearly 50 per cent. in excess of the present requirements; that during the summer there were plenty of cars and no orders, and during the winter there were plenty of orders but no cars. 2. That the mines were not properly developed from an engineering standpoint, and that the recovery of the coal varies from 50 per cent. to 95 per cent. 3. That this industry, employing over 600,000 men, could, if running full time, release 100,000 men for other work. 4. That the studies made by the engineers of the Fuel Administration showed that the cost of production increased with a loss of time and that with a 50 per cent. operation the increase in cost was about 40 per cent.

Jan 1, 1920

By P. Barnes

If it be admitted that the use of the metric system of measurement is desirable, and that it will be well, as urged by one of our engineering societies, to show upon all our plans or drawings a metric scale in addition to a scale of inches, then it becomes important to introduce some ready means of drawing these scales. For many present purposes it is quite sufficient to space off and to draw them with the common dividers and the right-line pen, but if the number of drawings made or copied in an engineer's office, and upon which scales must be shown, is more than two or three daily, then some more mechanical or automatic means should be provided. For a great majority of detail drawings, a simple transcript of the surface of a good two-foot rule would answer every purpose, and probably the best comparative showing of the metric scale would be made by drawing a line of millimeters close by the side of the line of sixteenths. This would be in fact little more than the

By Rex O. McLellan

The formation of a monovacancy in a metal is simulated in an elastic model by the displacement of the surface of a small spherical cavity in a large elastic continuum. The application of linear elasticity to this distortion results in a well- known formula for the energy and an expression for the concomitant entropy change due both to the shear strain in the continuum and also to the dilation of the solid resulting from the boundary conditions at the surface of the solid. Elastic data (the sliear modulus and its temperature coelficient) are used to calculate the entropy and energy of formation for many metals. Despite the simplicity of the assumptions involved, the agreement between the calculated entropies and energies and experimental values is remarkably good. In recent years there has been a large increase in measurements of the absolute concentration of mono-vacancies in metals as a function of temperature. Hence new data for both the energy and the noncon-figurational entropy of formation of monovacancies has become available. Recent measurements&apos; of the anomalous (non-Arrhenius) self-diffusion in many bcc metals has also focused interest on the prediction of the thermodynamic parameters of mono- and multi-vacancies in those metals for which no data are available. Damask and Dienes&apos; have discussed the various theoretical calculations of the energy of formation EL, of a monovacancy. These include simple models involving the breaking of atomic bonds on moving atoms from the interior of a crystal to the surface, models combining elastic calculations with surface-energy terms and detailed quantum mechanical calculations. The simler models give the correct order of magnitude of &, but tend to overestimate it by a factor of about two. The quantum mechanical calculations4"7 have been carried out for the noble and alkali metals with generally reasonably good agreement with the available Ef data. The calculation of entropy of formation Sfv14 lnvolves a fundamental calculation of the perturbation of the phonon spectrum caused by the creation of a vacancy. Huntington, Shirn. and wajda8 have given an approximate evaluation of sJV by considering an Einstein model for the localized vibrations in the immediate neighborhood of the defect and then using elastic theory to calculate the entropy associated with the shear stress field in the distorted crystal (as originally proposed by Zenerg). They also included a term due to the dilation of the crystal. They obtained a value of 1.47k for copper, in good agreement with the experimental value (1.50k). However, Nardelli and Tetta- manzi1° have recently shown that neglecting the coupling between atoms (Einstein Model) may lead to a serious error so the agreement may be somewhat fortuitous. In this work simple linear elastic theory is used to calculate the entropy and energy of formation of mono-vacancies. Despite the simplicity of some of the assumptions involved, the agreement with the available experimental data is remarkable. However. the reasonable degree of success in the application of linear elastic calculations to the excess entropy of a solute atom in a dilute solid solution1&apos; indicates that the application of elastic theory to vacancies. where the interaction of different atomic species is not involved, may not be inappropriate. THE ELASTIC MODEL The metal is assumed to be a spherical elastic continuum. A small spherical cavity of volume V = 4i;v:&apos;/3 is cut from the center. removed. and dissolved rever-sibly in the bulk of the material. TO a good approximation no net atomic bonds are broken and the material does not undergo a volume change although the externally measured volume of the body would increase by V. The radius of the sphere of metal is much larger than r Next a negative pressure is applied to the cavity causing its surface to be displaced inward by an amount simulating the relaxation of the lattice around a monovacancy. In this model the energy and entropy accompanying the distortion are taken as 4, and <. As a first approximation the equation of state for the solid is taken as: r = ro(i + *~D LiJ where K is the bulk modulus. P the hydrostatic pressure. Vo the volume of the material at 0°K and zero pressure. and d+/dT = 30. where 0 is the linear thermal expansion coefficient. The variation of entropy with hydrostatic pressure is given by the Maxwell equation: These equations give the entropy change resulting from increasing the hydrostatic pressure from 0 to P as: and since • we have: This is the entropy arising from the dilation resulting

Jan 1, 1970

By W. W. Yankie, A. T. Chatas

This paper is written as a discussion of the paper, "Buckling of Tubing in Pumping Wells, Its Effects and Means for Controlling It" by Arthur Lubinski and K. A. Blenkarn, which war published in the March, 1957, issue of Journal oP Petroleum Technology. An analogy is drawn between the buckling of tubing in pumping wells and a fiube, fitted with frictionless pistom, linked by an inelastic rod, and which is subject to an internal pressure. A simple derivation shows that the critical internal pressure exerts a hydrostatic force on the pisfon which is close to the Euler load for compression buckling of the same tube. While the results agree with those of Ref. I, the basis of calculations has been changed and clarified. The presence of internal upsets at the pistons is discussed. INTRODUCTION In the Appendix, Lubinski and Blenkarn state that a tube with ends closed by frietionless pistons connected by an inelastic rod (Fig. 1) will behave as a column loaded with a force equal to the tension force in the rod. They note that, while the fluid may not resist a shear force, the moment in every cross section is piston force multiplied by the elastic line deflection (c.f., the loaded column). Since the equations of the elastic lines are similar in the two cases, the solution is carried over from the loaded column. On the contrary it is suggested that while the method of solution remains unchanged from the column case, the actual stress distribution is different, a fact which is taken into account in this note. A simple method of approximating the buckling pressure is given, and their reasoning in our mathematical language is continued. GENERAL EQUATIONS The equation of an elastic line, initially straight in the x direction (Fig. 2), is given by In the case of a loaded column, this may be written: For the pressurized tube it was shown, by analogy with the loaded column, that tion has a solution that, for P, = EI/P, any deflection is stable (a criterion for buckling). An attempt will be made to describe more precisely, the forces acting on the tube, and to analyze the buckling condi,tions. DISCUSSION If the tube assumed a deflected position, the volume between the pistons would increase so that in deflecting, the energy of the fluid would decrease. When the increase in elastic energy of the tube (due to bending) is equal to the decrease of fluid pressure energy, buckling conditions exist. Analyzing the forces on the tube (Fig. 3), two transverse forces, T,, T,, exerted by the pistons, are balanced by a resultant of the pressure elements which are linearly dependent on the local curvature of the elastic line (Fig. 4). Unlike most buckling cases, the forces depend on the shape of the elastic line, a condition that makes a rigorous mathematical treatment difficult. Several approximations may be used to clarify the problem.

By A. O. P. Casbarian

An analytical method is developed to determine the variation of the ultimate lateral resistance of a plate in a cohesionless soil with depth. This analysis is based on a modification of Rankine&apos;s classical earth pressure theory and the theory of plasticity as applied to soils. The ultimate resistance is defined as the product of the effective stress at the midpoint of the plate, the area of the plate and a dimensionless variable termed the ultimate resistance factor. This variable has been plotted us the depth ratio: i.e., the ratio of of the depth of embedment us the height of the plate. The resistance of a plate may then be calculated using the values af the ultimate resistance factor from the chart provided or the equation may be programmed for use in an analysis of anchor systems in cohesionless soils. It is emphasized that the analysis is semitheoretical. The theory has been compared with experimental results reported in the literature and results indicate general agreement. Actual field tests are necessary to further verify this theory. INTRODUCTION With the exploration for oil offshore in waters all over the world, it is of importance to determine the behavior of the various soils in relation to their ultimate resistance to deformation. Examples of such problems are the holding capacity of anchors and the lateral resistance of piles. Very little information is available in the published literature on the design and performance of anchors, in either cohesive or cohesionless soils. The analysis developed in this report is the first step in obtaining a solution for the determination of anchor holding capacity in a cohesionless material. DISCUSSION The theory used in the analysis is based on the ultimate strength of the soil and is the maximum resistance developed by the plate against further movement. In such a state the elastic deformations are disregarded in comparison with the plastic deformations. Hence, the plate can be considered as completely rigid. The theory of plasticity determines the three unknown stresses at any point by means of two equilibrium conditions for a small earth element in combination with the failure condition. However, the exact solutions can only be carried out in a few simple cases such as, for example, when the rupture or failure lines are straight (Rankine theory) or with spiral and straight rupture lines (Prandtl theory).l Kiitter 2 derived a single equation expressing the variation of the stress in any given rupture line. To utilize this equation, it is necessary to know the stress in the rupture line at a certain point. Unfortunately, this is difficult to obtain unless the rupture line intersects the free surface at a certain angle or when the earth is cohesion-less and unloaded. A method to overcome this is to consider only the boundary conditions at both ends of a rupture line without investigating the equilibrium of the earth above the rupture line. This assumes that the rupture lines meet the surface at statically correct angles, so that boundary stresses may be determined. As Kiitter&apos;s equation furnished a relation between these stresses, the unit earth pressure may be calculated at the point where the rupture line meets the wall. Another way in which Kotter&apos;s equation may be applied is in investigating the equilibrium of a soil mass above a rupture line. This method assumes that the failure or rupture line is known and that the boundary stresses in the rupture line at the ground surface can be determined. In this case it is possible to determine the earth pressure from the equations of equilibrium.

Jan 1, 1967

By H. J. Wasson

DEVELOPMENTS in Venezuela during the past few months have been obscured by the hap-penings in Seminole and, more recently, those in southwest Texas. The question has been asked whether or not the opening of these vast new, prolific areas in the United States may not have depressed prices to a point so low as to give the developments in the Caribbean countries a serious setback. Nothing of the kind, however, has taken place, and on the contrary, there has been demonstrated the fact that Venezuela can profitably produce great quantities of oil under existing market conditions, and at the same time finance the foundation for further large expan-sion in the future. The three big factors which contribute to place Venezuela in a unique position and tend to insure the steady expansion of its oil industry are, in the order of their importance: I. Reasonable oil laws backed by a sound govern-ment, which comprehends the all-important fact that the country&apos;s prosperity depends on the prosperity of its industries, in a word, perceiving that the goose which lays the golden egg merits considerate treatment. II. The low cost of placing Venezuela oil on our At-lantic seaboard; not over $0.60 per barrel. III. The uniformly high average production per well and the large area of some of the individual pools. Under these conditions Venezuelan producers may be expected to continue steady and profitable ex-pansion even in the face of further market slumps. Their position is analogous to that of the low-cost copper producers, and unless artificial barriers, such as tariffs, come into play, Venezuela will steadily grow in importance. Within less than five years it should be second only to the United States among the oil-producing countries of the world.

Jan 10, 1927

By V. O. Struebing, K. A. Johnson, F. H. Ellinger, C. C. Land

The system Pu-Ce-(Pu,Ce)Co2 has been investigated by thermal, micrographic, and X-ray diffraction methods. The principal characteristics of this system were found to be: 1) a "eutectic" valley extending across the phase diagram from the 6 Pu/Pu3 Co eutectic at 408°C to the 7 Ce/Ce24Co11 eutectic at 42Z°C, the maximum temperature in the valley being 443°C; 2) three ternary inter mediate phases, each having an appreciable mutual solid solubility for plutonium and cerium; 3) eleven four-phase equilibria comprising one eutectic, four peritectics, and six Class II reactions; 4) a pseudobinary section between the ternary phase A and the y Ce solid solution, and another such section between the 6 Pu solid solution and the 77 phase (Pu3 CO) containing cerium in solid solution. ALLOYS of plutonium that are completely molten at temperatures in the vicinity of 500°C are of interest for use in the liquid state as fast reactor fuels. Since exploratory work1,2 on Pu-Ce-Co alloys had indicated that a "eutectic" valley extended across the ternary system between the Pu-co[6 Pu/n (Pu3co)] and the Ce-CO[? Ce/? (ce24co11)] binary eutectics, thus allowing alloys of any plutonium concentration to be selected within the temperature limitation, the present investigation was begun for the purpose of accurately defining the "eutectic" valley. However, when the existence of three ternary intermediate phases and the consequent complexity of the liquid-solid equilibria were discovered, the investigation was expanded to cover the complete system, except for the corner between the isomorphous series PuCo2-CeCo2 and pure cobalt. 1) EXPERIMENTAL The purities of the alloy components are given in Table I. Alloy buttons, each weighing about 5 g, were prepared by arc melting the accurately weighed components (±0.1 mg) under a purified He-Ar atmosphere. Weight loss as a result of melting was usually less than 1 part in 1000; therefore, the buttons were not chemically analyzed. One half of each button was re-melted by induction heating in vacuo in a magnesia crucible and furnace-cooled, so as to produce a somewhat coarser microstructure than that of the rapidly cooled arc-melted button. About 20 g of each alloy to be examined by thermal analysis were remelted in vacuo in a tantalum crucible of the inverted thermocouple well type. The thermal, X-ray diffraction, heat treating, and micrographic methods used in this investigation were essentially the same as have been described in earlier reports.3,4 Two etchants for these alloys were found to be satisfactory: A) 8 (parts by volume) orthophosphoric acid, 5 ethanol, and 5 glycol; B) 7 tetraphosphoric acid, 36 water, and 57 2-ethoxyethanol. Etchant A was used at 5 to 6 v for 15 to 20 sec, and etchant B was used at 10 v for 10 sec. 2) THE LIMITING BINARY SYSTEMS 2.1) Plutonium-Cerium. The phase relationships of this system have been investigated by Ellinger, Land, and Cramer,5 and by Selle and Etter.6 The over-all agreement of their phase diagrams is good, but there are some discrepancies in the positions of some phase

Jan 1, 1967

By H. Rosenthal, A. L. Jamieson

The action of mercury on stressed brass to produce cracks was known before Moore, Beckinsale and Mallinson1 showed that actual season cracking did not occur spontaneously but could be induced by ammonia. These investigators studied other substances, including diphenylamine, without finding that anything other than ammonia could cause season cracking Grimston2 reported season cracking in cartridge cases stored in wooden boxes wetted with dilute sulphuric acid pickling solution. Season cracking associated with sulphur dioxide, water vapor and air has been reported by Johnston,3 although he reported that trimethylamine and pyridine did not cause cracking. Jevons4 has ascribed season cracking of brass in certain instances to trimethylamine, "aldehyde amine," "ketone amine" and pyridine, but no experimental work was done evidently to prove this definitely. Pyridine was investigated by Morris,5 who found it to have considerable cracking power. In the present investigation, the object was a qualitative evaluation of a number of representative amines with respect to their ability to cause season cracking. Thus it was desired only that an appreciable vapor pressure of each amine be obtained in order to make the test as severe as possible, without attempting to test equivalent concentrations for comparative purposes. MEthods Specimens TWO types of specimen were used: 1. Unannealed 70-30 brass CUPs formed from 0.040-in. thick sheet. Height of cup Was 13/8 in. and diameter was 17/8 inches. 2. First draw pieces of caliber .50 cartridge cases in the unannealed condition (70-30 brass)- The cups were representative of a thin wall and thin base specimen, whereas the draw pieces have a thick base (1/4 in.) and a thick wall (approximately 3/32 in.). Both types of specimens contained high residual stress and cracked in less than one minute in a solution of I per cent mercurous nitrate and I per cent nitric acid provided that this was receded by a 30-sec. pickle in 40 per cent nitric acid. Specimens were prepared as follows: (1) degreased in trichlorethylene, (2) rinsed in H2O, (3) pickled 5 min. in 10 per cent by volume H2SO4 (1.84 SP. gr.), (4) rinsed in H2O, and (5) dried. Amirtes Tested In selecting the amines, representatives of the three series of amines, and one series of substituted amines were chosen. The aliphatic series was represented by the methyl and ethyl primary, secondary and tertiary amines. These are the simplest aliphatic amines. For the aromatic series, the phenyl primary, secondary and tertiary amines were selected as being the simplest. The heterocyclic series was represented by pyridine, which is a simple heterocyclic base (tertiary amine).

Jan 1, 1944

By P. A. Beck, A. H. Lutts

IN the classical picture of recrystallization the growth of strain-free grains at the expense of a strained and work hardened matrix is responsible for the softening of cold worked metals on annealing. It has been commonly assumed that the release of the stored energy of cold work, softening, and re-orientation take place simultaneously, as the high angle boundaries of the new recrystallized grains sweep over the cold worked matrix. However, recent evidence indicates&apos;,&apos; that, at least in some cases, considerable or even complete soften- ing may take place essentially without reorientation (i.e., without the migration of ordinary high angle grain boundaries, or "recrystallization&apos;&apos;) and the release of most of the stored energy of cold work may precede softening. These cases suggest that the property changes, taking place during the annealing of cold worked metals, may be associated with various distinct processes. The study of such situations is of considerable interest, since quantitative data are still scarce. In the present work, isothermal softening curves were determined for a heavily rolled aluminum single crystal, under such conditions that no "recrystallization" occurred until after complete softening. The hardness data were correlated with X-ray diffraction pinhole patterns in order to detect any reorientation that may occur and with measure-

Jan 1, 1955

By John F. Abel

"The most conservative persons I ever met are college undergraduates." Woodrow Wilson said that in 1905. No one is saying anything like it today. Chaos on the campus was a cliche of the sixties. Since 1905, education has expanded in every direction. Many more people are being educated for much longer periods of time. The school-leaving age has risen from 14 years to 20 years, on an average. Many are in school until after their 25th birthday. On the surface this situation appears all to the good. Our technical society needs a massive yearly infusion of semitrained (or educated, if you prefer) new blood. The efficiency of our economy and our standard of living are tied to high individual productivity which can be achieved only with an educated work force. Our democratic institutions are said to be founded on an educated electorate.

Jan 1, 1970

By John Chipman, Theodore B. Winkler

In order to understand more fully the complexities of the reactions occurring between the liquid steel and the slag in the basic open-hearth steelmaking furnace, investigations in this country and. abroad have turned to laboratory equilibrium studies. This paper is one of a series of reports on investigations being conducted at the Massachusetts Institute of Technology. The experimental work was completed early in 1942. The slag systems found in the basic open hearth are very complex, being made up of at least eight major components and as many others whose effect might be classified as minor. The first two papers of the series, by Fetters and Chipman,l,2 as well as the paper by Taylor and Chip-man,3 dealt with the simplest possible slag system that would resemble those found in the basic ope), hearth—the slag system consisting of CaO-MgO2-SiOz-FeO. (Taylor&apos;s rotating induction furnace eliminated the necessity of contamination of the slag by MgO.) Having arrived at some reasonable conclusions regarding the physical chemis- try of the reactions between molten iron and the simple slags at equilibrium, the next step was to investigate more complex slag systems. The major purpose of the present investigation was to determine what factors control the distribution of phosphorus between molten iron and the more complex basic slags at equilibrium, and to what extent these factors are influential. The slags used contained CaO, MgO, SiO2, FeO, Fe2O3, P2O6, MnO, Al2O3 and CaF2, but not all of the slag samples contained all of these components at one time. Review of Literature Although a number of interesting papers have been published on the subject of dephosphorization of an iron bath, there are as yet no results from laboratory studies that give thoroughly reliable information on the dephosphorization reaction. Even for the supposedly simple Fe-O-P system involving iron-phosphorus melts and iron oxide-iron phosphate slags, the experimental results are contradictory and no formulas have been established that adequately fit the equilibrium conditions. The Fe-O-P system has been studied by Schackmann and Krings,4 von Samson-Himmelstjerna,6 Oelsen and Maetz,6 Bischof and Maurer,7 Diepschlag and Schürmann,8 and Herty,9 and the results of their investigations appear in Table I. A number of different equilibrium constants and distribution . Ratios

Jan 1, 1947

By Theodore B. Winkler, John Chipman

In order to understand more fully the complexities of the reactions occurring between the liquid steel and the slag in the basic open-hearth steelmaking furnace, investigations in this country and. abroad have turned to laboratory equilibrium studies. This paper is one of a series of reports on investigations being conducted at the Massachusetts Institute of Technology. The experimental work was completed early in 1942. The slag systems found in the basic open hearth are very complex, being made up of at least eight major components and as many others whose effect might be classified as minor. The first two papers of the series, by Fetters and Chipman,l,2 as well as the paper by Taylor and Chip-man,3 dealt with the simplest possible slag system that would resemble those found in the basic ope), hearth—the slag system consisting of CaO-MgO2-SiOz-FeO. (Taylor&apos;s rotating induction furnace eliminated the necessity of contamination of the slag by MgO.) Having arrived at some reasonable conclusions regarding the physical chemis- try of the reactions between molten iron and the simple slags at equilibrium, the next step was to investigate more complex slag systems. The major purpose of the present investigation was to determine what factors control the distribution of phosphorus between molten iron and the more complex basic slags at equilibrium, and to what extent these factors are influential. The slags used contained CaO, MgO, SiO2, FeO, Fe2O3, P2O6, MnO, Al2O3 and CaF2, but not all of the slag samples contained all of these components at one time. Review of Literature Although a number of interesting papers have been published on the subject of dephosphorization of an iron bath, there are as yet no results from laboratory studies that give thoroughly reliable information on the dephosphorization reaction. Even for the supposedly simple Fe-O-P system involving iron-phosphorus melts and iron oxide-iron phosphate slags, the experimental results are contradictory and no formulas have been established that adequately fit the equilibrium conditions. The Fe-O-P system has been studied by Schackmann and Krings,4 von Samson-Himmelstjerna,6 Oelsen and Maetz,6 Bischof and Maurer,7 Diepschlag and Schürmann,8 and Herty,9 and the results of their investigations appear in Table I. A number of different equilibrium constants and distribution . Ratios

Jan 1, 1947

By Edmund Davenport

THE specific aim of this work has been to study certain forms of internal deterioration which occur in tungsten filaments when subjected to high temperatures under various conditions, and to determine the cause of such deterioration. This would naturally lead to a consideration of methods of control or means of prevention of the phenomena. The deterioration was first noticed as a peculiar condition in the grain boundaries of certain tungsten filaments which had been burned? for long periods in lamps. In these cases it was noted that the grain boundaries contained a number of minute black dots which were at first thought to be non-metallic inclusions. It was demonstrated later that these dots or pits, as they were designated, could be readily produced by burning filaments in an atmosphere of flowing hydrogen. This method was convenient and adequate for the purpose, and was adopted for most of the work discussed in this paper. The evidence accumulated to date indicates that these pits are actually small voids between the grains. The purpose of this paper is to present- the information on this interesting subject gathered during a period of about 3 years. As applied to tungsten, the subject appears to be of considerable importance, experience having shown that this pitting ?is frequently associated with poor performance of filaments in lamps. The question has arisen as to whether these intergranular pits are peculiar to tungsten, or if they occur in all metals. If they are found iii all metals, the facts will be of considerable theoretical interest, as the material at the grain boundary plays an important part in most of the current theories of the properties of metals and alloys.

Jan 1, 1927

By Jo. E. Sheridan

The Dawson coal-mines are owned aid operated by the Stag Canon Fuel Co., of which Dr. James Douglas is President and E. L. Carpenter general manager. The property is situated in Colfax county, N. M., and the openings now in operation are in townships 28 and 29 N R. 20 E., and township 28 N E. 21 E., shown in Fig. I. The mines are part of the southern end of the Raton coal-field, which extends north into Colorado and embraces many coal-camps of the Trinidad section. II. Geology. Geologically, the coal-measures, commonly known as the Laramie series of the Cretaceous system, have x thickness of about 800 ft. in the vicinity of Damson. The coal makes an excellent coke, and, according to some authorities, its coking properties are due to the action of intruded sheets and sills of igneous rock, the sheets occasionally thickening into masses resembling laccoliths, at such places making nearer approach to the coal and sometimes producing small areas of natural coke. There are but few dikes throughout the entire southern portion of the field and little or no faulting along the dikes. In some parts of this great coal-field the intrusive sheets are far removed in the green shales below the coal-measures, and are so much altered as to be difficult of identification. There is but little disturbance of the strata throughout the Raton coal-field in as far as it extends into New Mexico. There are two workable seams in the coal-measures, and two or three smaller coal-seams, ranging from 1 to 2.5 ft. in thick-

Jan 1, 1910

By N. J. Grant, B. C. Giessen, M. Morris

The slvuclures of alloys in the system In-Bi have been investigated after (levy vapid queuching from the mell (splat cooling) to -190°C. Tuo-phase fields could be suppressed over most of the tota1 concentvalion range; five melastable phases a1, a2, ?, ?1. and ß exisl, of which four have simple elementtike structures. For example, ß has the A5 struclure of white till. Crystal-tographic data and coordination numbers for these phases aye given, as well as addilional information on the equilibrium diagram, where a new phase In5Bi3 teas found. THE phase diagrams of binary combinations of B elements from the groups B2, B3, B4, and B5 are usually of a simple type and show considerably fewer intermediate phases than combinations of these elements with A metals, transition metals, or the B1 noble metals. Aside from phases such as the typical B3-B5 compounds with the ZnS-B3 structure type, few stoichiometric phases are known; among them are In2Bi and 1nBi.l Nonstoichiometric phases include ß (In-Sn), a1, (In-Pb), and the tin-rich ? phases in the In-Sn, Cd-Sn, and Hg-Sn systems.&apos; The first two phases have a close relationship to indium, while the latter group are known to be structurally related to a Sn. Thus, there are generally no immediate experimental data for the correlation of the crystal structures of B metals and B metal combinations with certain monotonously varying parameters, such as the valence electron concentration (VEC), or the average atomic size. Such parameters have been recognized as structure determining, e.g., for the transition 4 Sn — y phase,2,3 where nonintegral valence electron concentrations are encountered. It should be possible to extend such correlations to other binary systems, if nonequilibrium single-phase alloys could be produced over broad valence electron concentration ranges, and if their crystal structures could be regarded as being imposed by their electronic states. It has been shown in the case of the tin-rich 7 phases3 that alloy phases with typical crystal structures can be produced in B metal alloys rapidly quenched from the liquid to -190°C by the splat cooling technique due to Duwez,3-8 and reviewed in Refs. 5 and 6. The In-Bi system was selected because it extends over a valence electron concentration range in which several metastable, nonstoichiometrir phases could be expected to occur. Further, the low melting points of the known intermediate phases, In2Bi and InBi, Fig. 1(a), indicated low binding energies and thus possibly low driving forces for the formation Of the equilibrium structures. EXPERIMENTAL TECHNIQUES AND RESULTS The preparation of the quenched foils followed the practice described in Ref. 3. Master alloys were produced by melting of indium (99.97+) and bismuth (99.99+) in evacuated Vycor capsules or in an inert gas arc furnace; quantities of 20 mg were splat-cooled onto copper and silver substrates held at - 190°C; and crystal structures and lattice parameters were determined on a GE XRD-5 diffractometer using Cu Ka, radiation at -190°C and at room temperature. The duplication of each run with both substrates permitted the elimination of overlap of the substrate diffraction pattern and that of the investigated substance. The XRD patterns were usually taken from sin2 " = 0.03 to 0.35; the substrate was used as a means of internal calibration. The fractional accuracy of the lattice parameters of metastable phases is approximately 10-3 In the following, all percentages are in atomic percent. The stable and metastable phases found after rapid quenching to -190°C are listed in Table I, together with estimated concentration ranges and crystallographic data. The investigated alloys and phases present in them are given in Table 11. Except for the region between indium with 33 and 50 pct Bi, where a revision of the equilibrium phase diagram became necessary to include a new stoichiometric phase In5Bi3, the diffraction patterns taken after heating to room temperature agreed with those expected from the phase diagram, Fig. l(a). This suggests that the new nonstoichiometric phases are not stable at room temperature, thus following the observations made for the y phases based on tin.3 Results concerning the equilibrium phases In2Bi and In5Bi3 and the revision of the equilibrium phase diagram which is made necessary by the inclusion of In5Bi3 will be treated first. The Crystal Structure of In2Bi. Makarov7 had identified In2Bi as belonging to the AlB2-C32 type ; however, in a later paper the structure was revised.8 In2Bio was found to be of the Ni21n-B8ß type,21 with a = 5.496A, c = 6.57.9A, and N = 6 atoms per unit cell.9 This crystal structure was confirmed in the present work; definite evidence for the doubling of the c axis, as compared to the A1B2-C32 type, and for the proposed order structure, was found in the powder pattern. The observed lattice parameters agree well with those of Ref. 8; those measured at -190°C are given- in Table I. The Crystal Structure of In5Bi3. A new, equilibrium, intermediate phase was identified in slow-cooled, as-cast alloys; it was identified as In5Bi3. The structure has been worked out by Giessen and Grant;" lattice parameters at -190°C are given in Table I. This phase is probably identical with "In3Bi2", produced by vapor deposition techniques, but not recognized as an equilibrium phase by Palatnik et a1.11 After completion of the present work, the existence of In5Bi3 has also been demonstrated by superconductivity measurements on In-Bi alloys.20

Jan 1, 1968

By W Lindlief, Cyril Stanley Smith

Several investigators, mainly concerned with the mechanical properties of the alloys, have studied the so-called aluminum bronzes after various quenching and reheating treatments. Of these works, perhaps the most complete is that of Bouldoires, who studied changes of length, electrical conductivity, thermoelectric force, hardness and micro-structure on tempering quenched alloys containing 5 to 20 per cent of aluminum, although the work of Carpenter and Edwards,² Curry13 Greenwood,4 Braesco,5 Matsuda,67 Grard8 and others has added much to our knowledge of the changes occurring during tempering. The so-called acicular ß decomposes on tempering at temperatures between 350" C. and the eutectoid, giving rise to a Widmanstätten structure of a needles in a matrix of 6 or fine a + 6, associated with an increase in hardness and almost complete loss of ductility. Matsuda studied the eutectoid transformation by means of dilatation and electrical conductivity measurements during cooling at different rates. He found that on cooling at the rate of 10" C. per minute there was a decrease in electrical resistance and in length instead of the usual increase which occurred with slow rates of cooling. On tempering the rapidly cooled samples, the increase commenced at about 400" C. and at 520" C. the resistance and length had reached the equilibrium values. These peculiarities he accounted for as being due to a transitional phase ß&apos; being formed, ß&apos; having an electrical resistance and volume less than either ß or a + 6. Obinata9 published some electrical conductivity curves for copper-aluminum alloys showing a double break at the eutectoid temperature,

Jan 1, 1933

By George W. Sears

In preparing this symposium, our ambition was to elicit authoritative expression of opinion concerning important selected phases of the industry from men active in it. Responses to requests for contributions were gratifying, especially so in view of the short time available. The generous and cooperative spirit of the industry as a whole is amply evident. Responses were received from the following, who are therefore the true authors of the paper: W. G. Adamson, General Manager of the pershin; Quicksilver Co., Lovelock, Nev.; Dudley Baird, Vice President, Pacific Foundry Co., San Francisco; Walter W. Bradley, State Mineralogist of California; W. D. Burcham, General Manager of the Brewster Quicksilver Consolidated, Terlingua, Tex.; William Forstner, San Francisco; H. W. Gould, of H. W. Gould & Co., San Francisco; Marcus Hulings, General Manager of the Chisos Mining Co., Terlingua, Tex.; Frank J. Katz, Chief Engineer, Division Mineral Statistics, United States Bureau of Mines, Washington, D. C.; Lloyd J. Lathrap, Superintendent, Nevada Quicksilver Mines, Inc., Lovelock, Nev.; W. R. Moorehead, General Manager, New Idria Quicksilver Mings, Inc., Idria, Calif.; F. W. Oakes, Jr., Terlingua, Tex.; C. N. Schuette, San Francisco. Brief Economic History of Quicksilver in the United States Quicksilver ore was first discovered in the United States at what was later the New Almaden mine in California, in the year 1824. Production also began here, but not until 1850, when it was stimulated by the active demand caused by gold-mining operations. Prospecting for quicksilver was active, high-grade ores were found and ample production lowered the price from $100 per flask in 1850 to about half that figure for the greater part of the next 10 years. During the succeeding decade, many new quicksilver mines were found; production increased at a time when the local demand diminished, so that most of the product was exported. The third decade of quicksilver mining in the United States witnessed the development of the pan amalgamation process, particularly in Com-stock silver-mining operations. A suddenly increased demand sent prices soaring, the all-time peak of quicksilver production followed, and the highest price was soon replaced by the lowest one on record. Huge quantities of quicksilver were exported between 1870 and 1880 and exports continued in decreasing measure for three decades to 1910. In

Jan 1, 1930