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By S. R. Goodman, Hsun Hu

The rolling texture transition in copper as a function of deformation temperature is found to be quite similar to that in high-purity silver. The ordinary copper type texture changes gradually to the brass type, accompanied by an increase in the stacking fault frequency, as the temperature of deformation decreases. The rolling textures obtained at low temperatures and the corresponding annealing textures compare remarkably well with the ordinary rolling and annealing textures of low-zinc brasses. Furthermore, it is also found that the observed stacking fault energies of copper specimens deformed at low temperatures correspond closely with those of low-zinc brasses, as deduced from measurements of the dislocation nodes. These results are consistent with the idea that texture transition may be significantly dependent on the stacking fault energy. It was shown in a series of previous publications1"3 that the rolling texture of high-purity silver changes gradually from the common silver type (or the brass type) to the copper type* with increasing temperature *The silver or brass type rolling textures are commonly described as (110)[112],4,5 whereas the copper type rolling textures are mainly (123) [a121 and (146)[211].5 Other ideal orientations have been used by various investigators for the copper type rolling textures, but the actual difference among these ideal orientations is rather small. of deformation, and that such texture transition can be correlated with the change in stacking fault frequency as a function of rolling temperature. Furthermore, it was shown that the formation of annealing textures in high-purity silver from the various rolling textures obtained during the course of texture transition depends entirely upon the deformation texture. From a common silver type or brass type rolling texture (such as produced by rolling at 0" or at 50° C) the recrystallization texture is mainly (120)[211], which is quite different from the recrystallization texture of brass.* However, for both ma- terials the orientation relationship between the rolling texture and the recrystallization texture can be expressed in terms of similar rotations around [Ill.] axes of approximately 30 or 35 deg. They differ in that the [Ill] rotational axes are different. In the case of high-purity silver, the axes of rotation are the two (111) poles near the plane normal of the deformed specimen with a (11l)[112] type rolling texture, whereas in brass, they are the (111) poles near the direction of rolling. For high-purity silver with a predominantly copper type rolling texture (such as produced by rolling at 150° or 200°C) the recrystallization texture is mainly (100)[001], or the cube texture, plus its twin orientations. It was shown previously6 that such reorientation observed in copper or aluminum can be described as [Ill] rotations of 30 to 40 deg. For intermediate cases, i.e., when the rolling textures are composed of a

Jan 1, 1963

[Note.—The paper of Mr. Hoffman on " Practical Results in the Magnetic Concentration of Iron-Ore " (page 602); that of Mr. Langdon on "The Use of Magnetic Concentrates in the Port Henry Blast-Furnaaces" (page 599); and those of Mr. Landis on "The Determination of Iron in the Tails from Magnetic Concentration " (page 609) and "Note on Sampling Iron-Ore" (page 611), were all prepared as contributions to this discussion.] The papers of Mr. Langdon and Mr. Hoffman were presented. W. H. Hoffman, Croton Mines, N. Y.: I will add a few remarks, by way of answer to inquiries for further details. The Croton Mines are particularly well located for cheap mining. The ore-bed is very large, and so lies in relation to the railway tracks of the Harlem and other railroads that a very large proportion of our mining for several years to come can be done above these tracks. The concentrating-mill is now 400 feet from where we are working in the quarry. In blasting we never remove less than 2500 tons at a blast,

Jan 1, 1892

By G. L. F. Powell, L. M. Hogan

Samples of silver and Ag-O alloy, 0.12 wl pet, have been undercooled to a maximum of 250°C by melting in a slag of commercial soda-lime glass. Grain refinement occurred in undercooled silver samples whet the degree of undercooling exceeded a critical value which varied from 153° to 175°C, depending on the melting conditions. In under cooled Ag-0 samples, the grain structure was fine and equiaxed at degrees of undercooling larger than 50oC. The grain refinement in both silver and Ag-0 alloy samples was the result of recrystallization during or immediately following freezing. When the oxygen content was increased, the degree of undercooling at which recrys-tallization occurred decreased. INVESTIGATIONS of the grain structure of strongly undercooled melts of nickel and cobalt1-4 have revealed a change in room-temperature grain size as a function of undercooling. At large degrees of undercooling the grain size was fine, but samples undercooled by smaller amounts exhibited a much coarser grain structure. The reported undercooling at which this grain size transition occurred in nickel varied between 140° and 175'C undercooling. Walker1 attributed this grain size change to an enhanced nuclea-tion rate. Cavitation at a melt-solid interface was con sidered to generate a high-pressure wave. This, in turn, produced nucleation in the liquid as a result of an elevated freezing point increasing the undercooling in the melt. A similar grain size transition was observed in undercooled silver between 133° and 153°C undercooling.5 The grain size transition in undercooled silver was found to be dependent on oxygen con tent. More recently, the authors5 showed that a simila transition occurred in an undercooled Cu-O alloy, =0.08 pet, but not in oxygen-free copper undercooled more than 200°C. The transition was attributed to recrystallization of the solidified grains after freezing; the greater the degree of undercooling, the more complete the recrystallization. In view of this effect of oxygen content on grain size transition, additional undercooling experiments were carried out with silver. This paper reports the results of these studies on silver and Ag-O alloys undercooled more than 50°C EXPERIMENTAL 1) Materials. The silver was supplied by Matthey Garrett Pty., Ltd., as fine granulate, silver mini' mum 99.9 pet, and contained the trace impurities shown in Table I. The silver originated from two different refineries resulting in the difference in impurity content shown in Table I. However, the variation in composition had no discernible effect on the undercooling behavior. Samples of the silver were melted in an open-ended, vertical, cylindrical resistance furnace, wound with Kantha] wire, the temperature of which was adjusted by means of a variable transformer, 2) Melting and Undercooling. Bulk samples of silver were undercooled by preoxidation and removal of oxidized impurities in a glass slag, as previously described,5 but special precautions were necessary to allow comparison between oxygen-free silver and a Ag-O alloy. Samples free of oxygen were prepared by first melting weights of granulate varying from 200 to 400 g in clean vitreous silica crucibles in air for approximately 15 min. A sample was frozen and a complete glass cover formed over the top surface by adding granulated glass rod. The sample was then melted and frozen several times until no oxygen bubbles appeared in the glass slag. Subsequent thermal analysis indicated that the oxygen content was negligible. The glass acted as an efficient barrier to absorption of oxygen from the air. Ag-O alloys were prepared by melting silver in silica crucibles with only a partial cover of glass, so that the top surface of the melt was in contact with air. The silver was held molten in air for several hours at 1000° to 1050°C, in the expectation that the oxygen in solution would reach equilibrium with atmospheric oxygen. At T - 1000°C the equilibrium oxygen content was calculated as 0.12 wt pet O, using Sieverts law and Eq, [l], derived by Mizikar et a!.7 from the data of Sieverts and Hagenacker8 for 1 atm of oxygen:

Jan 1, 1970

By J. H. Nelson

An outline survey of the economic outlook for the United States export trade in petroleum products resolves itself broadly into two general divisions; first, a consideration of our present position in this trade, and second, a discussion of the visible factors which promise to affect appreciable changes in the immediate future in that trade. The United States PetRoleum Exports of majoR Petroleum Products 1925, 1926 and 1927

Jan 1, 1928

By A. Goldberg, T. E. Tietz, J. E. Dorn

INTRODUCTION THE concept that the flow stress for plastic deformation of metals in the work hardening range is a function of the instantaneous values of the strain, strain rate and test temperature was promulgated by Ludwick1 many years ago. This thought has been more or less a guiding principle throughout the immediate period of development and growth of mechanical metallurgy. It has been tacitly assumed or knowingly applied to many investigations on the plastic behavior of metals. Spurred by the theoretical interest and practical importance of the plastic behavior of metals, many investigators have attempted to determine empirical, semi-empirical, and theoretical equations2-18 relating the flow stress with the strain, strain rate, and temperature. Although the applications of such equations have been extensive, the experimental verification of the existence of a mechanical equation of state is weak. Furthermore, some of the available evidence on plastic flow appears to suggest that no simple functional relation between stress, strain-rate, strain and temperature can exist. The mechanical equation of state demands that [a = a(e, E, T)[I]] Where o = true stress = load/instantaneous area e = true strain = In Instantaneous gauge lengths initial gauge length e = true strain rate T = temperature] This formulation implies that [da] is an exact differential. Therefore the flow stress (o) is a function of the instantaneous values of the strain (e) the strain rate (e) and the temperature (T), independent of the previous mechanical or thermal history. Having reached a certain strain, strain rate, and temperature, by any path whatsoever, a definite and fixed value of the flow stress should be obtained. One check on the validity of the mechanical equation of state is easily obtained. Consider the following three tests on the stress-strain curve at constant temperature: [A. Strain at rate [ei] B. Strain at rate i2 C. Strain at rate [Ei] to [ei] and continue test at i2] A graphical representation of possible results of such tests are shown in Fig I. If, for strains greater than [el], test (C) data coincide exactly with the data from test (B), as shown in Fig Ia, a limited verification of the mechanical equation of state is obtained for the range of strain rates from [ii] to [e2]. But if the data from test (C) differ from those of (B) beyond strain [el] where the strain rate is changed from [e,] to [€2i] the mechanical equation of state is not

Jan 1, 1948

By Gilbert Santoro

In this study tantalum carbide filaments of various compositions in the fcc region were prepared by heating a tantalum wire in a measured amount of hydrocarbon vapor. Such properties as tensile strength, transverse-rupture strength, microhard-ness, lattice parameter, electrical resistivity, and magnetic susceptibility were measured as a function of carbon content. Some of these properties showed a maximum or a minimum between a carbon-to-tantalum molar ratio of 0.80 and 0.85, the composition range at which the color changes from metallic gray to gold. The recent literature has shown that in the large homogeneity range for the fcc phase of the Ta-C system there is a marked variation for such properties as microhardness,' electrical resistivity, ' thermodynamic properties,z'3 lattice parameter and superconductivity. In addition to the technological interest of these variations within a single phase, important theoretical benefits may ensue from a continuous investigation of properties vs stoichiometry in tantalum carbide and other refractory defect compounds, for example the effect of the metal-metal distance and crystal structure upon bond formation and electronic structure. Whether there is a similar variation of the tensile strength is of practical importance. Of theoretical interest would be the knowledge of how the magnetic susceptibility varies with carbon composition. Both of these properties, as well as the transverse-rupture strength, were determined for tantalum carbide filaments in the fcc phase region. The lattice parameter, the electrical resistivity, and the microhardness were also investigated and compared with values appearing in the literature. EXPERIMENTAL PROCEDURE Material Preparation. Tantalum carbide specimens of various carbon content were prepared by statically carburizing high-purity tantalum filaments in measured quantities of pure hydrocarbon gas. The filaments, which were 10 mil in diameter and 20 or 40 cm long, were heated by their own resistance at temperatures from 1800" to 2200°C using alternating current in some cases and direct current in others. Tantalum wire from two sources was used. One had a reported purity of 99.96 wt pct Ta. The ingot from which this wire was drawn had been electron beam-melted as the final step in its purification. The reported purity of the other wire, which was prepared by a powder metallurgical process, was 99.88 wt pct Ta. The impurities of both tantalum sources are listed in Table I. Spec-trographic-grade toluene or research-grade propane was used as the source of carbon. The apparatus for the carburization of the filaments is shown schematically in Fig. 1. The system was evacuated to 1 x l0-' mm of Hg when using the electron beam-melted tantalum and to less than 1 p when using the less-pure tantalum. Neither the difference in the base vacuum, nor in the hydrocarbon gas, nor in the tantalum filaments resulted in any detectable difference in the properties studied in this work. However, only the carbides prepared from the higher-purity tantalum were used in the magnetic-susceptibility determinations. Once the base vacuum had been reached, the system was flushed with the hydrocarbon and re-evacuated. For any desired composition of the carbide, hydrocarbon gas was allowed to leak into a constant-volume flask to a predetermined pressure. These pressures were measured by a Cartesian diver-type mercury gage with a range from 0 to 20 mm and with a scale expanded to nine times. The hydrocarbon gas was allowed into the reaction tube and the filament was quickly raised to the reaction temperature. The slack in the filament due to thermal expansion was taken up by drawing out the movable electrode with a screw mechanism. The filaments were kept at temperature from a few minutes to 200 hr. In the majority of cases the heating time was 6 hr. The reaction tube was cooled by cascading water on its outer surface. By means of an ammeter and a voltmeter the electrical resistance at the reaction

Jan 1, 1963

By A. E. Bellis

THE CHAIRMAN (ALBERT SAUVEUR, Cambridge, Mass.).-Any information likely to throw light on the constitution and proper treatment of high-speed steel in order to obtain maximum results, should surely he welcomed. All users of high-speed steel, I believe, will agree with the authors that, in order to obtain satisfactory results, it is not sufficient to heat all brands of high-speed steel to one and the same temperature; apparently very slight differences of chemical composition seem to call for marked differences in temperature. I think that all of us agree that a properly treated piece of high-speed steel should have a fine austenitic or polyhedral structure and that an appreciable quantity of free carbide may be present in the case of very high tungsten steels. What we seem to lack is a satisfactory method, quick and reliable, of ascertaining when the proper structure has been obtained. I think Mr. Bellis' paper is a step in the right direction. To the untrained eye, however, it is not an easy matter to select from some of his photomicrographs the one representing the best structure; for instance, in the case of steel A, we wonder why temperatures of 2,250 and 2,300 do not yield the same results, seeing that both structures are apparently alike, and the same might apply to some of the other samples. I have no doubt, however, that the experienced observer is capable of detecting structural differences that are not made plain here and by which he is able to select the proper quenching temperature. COLIN G. FINK, East Orange, N. J.-On page 68 the authors say that the use of a barium chloride bath to eliminate this difficulty has the disadvantage that the surface of the tool becomes decarbonized." I would like to ask whether they actually found that the surface was decarbonized, or whether they base this conclusion on softening alone? A. E. BELLIS, Springfield, Mass.-No, we have never demonstrated that it was a decarbonization, it is just the softening of the steel. The addition of ferrocyanide to the ferrochloride bath has been suggested. I think that is not altogether satisfactory, because the ferrocyanide bath changes composition very rapidly at these high temperatures, and it would be just a question of luck whether or not it had too much or too little ferrocyanide in the bath giving equilibrium with the carbon content.

Jan 4, 1917

By Frank Kneeland

SAFETY FIRST is a popular motto-most mining companies have adopted it. It is probable, however, that in the majority of cases it is only a motto and gets no further than the office stationery or the bulletin board at the mine's entrance. In but few industries is there employed a greater diversity of machinery and mechanical devices than in coal mining. The list ranges all the way from mechanical stokers to wood-working machinery and undercutters. Many of these devices, particularly those employed in wood working, are extremely dangerous. In 1913, 23 per cent. of all fatalities occurring in coal mining in the U. S. were caused by machinery of some sort or other. Although the forms of accidents occurring with mining machinery are legion, they generally arise from one or more of five causes: (a) Falls from ladders, platforms, etc.; (b) coming in contact with moving machines or parts thereof; (c) electric shocks; (d) failure of some machine part; (e) mismanipulation of valves, levers, switches or other hand-operated controlling devices. The steps which may be taken to prevent accidents from the above causes are almost as numerous as the accidents themselves. There is, and can be, no panacea for all mishaps, nor for any one class of accidents. There is no mathematical or other formula that will bring immunity under any set of conditions. Common sense is the only guide. The remedy for the first-named class of accidents is simple and generally effective-namely, make the staging, ladder, platform, or other support, abundantly strong to carry any possible weight that it may be called upon to bear; provide ample railings on platforms or runways, and non-slipping feet on movable ladders.

Jan 1, 1915

By L. G. Huntley

The occurrence of oil or "tar" in Mexico was mentioned as early as the seventeenth century by Friar Sagahun, who gives the Indian name "chapopote," by which these asphalt seepages are still called. This asphalt was apparently used, as it has been used by primitive people in many parts of the world, in religious ceremonies and for medicinal purposes. Travellers also report that the ruins in Yucatan and the pyramids in southern Mexico show traces of the use of "chapopotel' as a building cement.l DeGolyer says that the first attempt to exploit oil or gas in Mexico in a commercial way is shown by the records of the Memoria de Fomento of 1865, when permission was granted to a Senor Ildefonso Lopez to exploit the deposits of petroliferous substances in the San Jose de las Rusias area in the State of Tamaulipas. Other concessions follow, and probably refer to surface seepages which occur in that district. This was several years after the discovery of oil in Pennsylvania. In 1868, a well 125 it. deep was :drilled by a company organized in Mexico City, in what is now known as the,, Furbero district, and a little oil was refined there. In 1873, residents of Tampico denounced seepages along the Tamesi River, and asphalt was mined near Tempoal in the Canton of Tantoyuca. No drilling was attempted. But between 1880 and 1883 several shallow wells were drilled for oil in Mexico, two of them being near the present Potrero de Llano field west of Tuxpam. The wells were drilled by a Boston company with Canadian rigs, and are said to have reached a depth of about 400 ft., while one is reported to have flowed. Several other abortive attempts were made to drill for oil between 1885 and the beginning of the present century, about which time the Mexican Petroleum & Liquid Fuel Co., Ltd., in which Cecil Rhodes was interested drilled 24 wells unsuccessfully, several of them as deep as 1,500 ft., in the State of Vera Cruz. Also Messrs. Doheny and Canfield of California pur-

Jan 1, 1916

By F. E. Jaumot, R. L. Smith

Self-diffusion in zinc has been used as an instrument for comparison of the absorption and sectioning techniques as a means of studying diffusion. Single crystal as well as poly-crystal samples were used asanda the temperature range of diffusion extended from 200° to 415°C. For temperatures above 200°C, the data indicate that the results obtained from the absorption technique agree with those obtained from the sectioning technique. The effect on the values of the diffusion coefficient of electroplating vs evaporation as a means of applying the tracer was investigated and no significant difference observed. It was found that an excess or deficiency of tracer did not materially affect the results obtained from the sectioning technique, but invariably caused errors with the absorption technique. NEARLY all self-diffusion experiments and many alloy diffusion experiments have employed radioisotopes as the instrument for following the diffusion. Of the various techniques in which radioisotopes are applicable, the two most widely used are the sectioning and absorption techniques. In the former, the diffusion coefficient is obtained from a curve of log concentration vs the square of the mean penetration depth. In the latter, the diffusion coefficient is calculated from a knowledge of the decrease in activity at the surface after diffusion. In spite of the importance of knowing the reliability of the diffusion data and the widespread use of these two techniques, they had not been directly compared experimentally on the same samples. Thus, such a comparison was worthwhile. The specific system chosen for this comparison was the self-diffusion of zinc, since the metal was readily obtainable in high purity, single crystals were easily grown, and the anisotropic features of the diffusion added an additional factor of interest to the comparison. Self-diffusion in both single and polycrystals was investigated, since the possibility existed that grain boundaries and grain boundary diffusion might produce different effects for the different techniques. Also, the effects of electroplating vs evaporation as a means of applying the radioactive tracer, and the effects of applying an excess or deficiency of tracer material were studied. The general experimental procedures and the mathematical analyses of both techniques have been described previously in some detail, and only those points essential to an understanding of the present work will be discussed here. The mathematical analysis of the sectioning data requires only a knowledge of the solution of Fick's equation. where C,, is the initial concentration, C is the concentration at depth x, D is the diffusion coefficient, and p is the absorption coefficient of the solvent metal for the radiation from the solute. Having obtained F from the experiment, the value of z can be read from a plot of F vs In z, and D can then be calculated if is known. The necessity of knowing the absorption coefficient causes most of the criticism of the absorption technique. It is very difficult to measure accurately under the conditions existing in the diffusion experiment, but it is absolutely necessary, as will be indicated briefly later. Portions of this problem have been discussed in detail elsewhere." The difficulties involved in the measurement of the absorption coefficient arise from three principle factors: the physical characteristics of the absorber, the geometry, and complex radiation spectra. The first two are heavily dependent upon the third. If

Jan 1, 1957

By P. L. Menaul, P. P. Spafford

This paper discusses the most dangerous form of corrosion encountered in condensate-well oil production, the discovery of the agent causing this corrosion and the remedial chemical treatment proved effective by field use. The injection of ammonium hydroxide, even as little as one quart per day, has proved effective in preventing gas-condensate well corrosion. The injection of "Bone oil" is applied to wells producing brines containing calcium and magnesium salts. Introduction The severe corrosion of equipment in high pressure gas condensate wells has been a problem for several years and numerous papers have been presented on the subject. The term "gas condensate" or "distillate well" is applied to a distinct variety of hydrocarbon producing well, the characteristics of these wells being high bottom-hole (formation) pressures and temperatures and high gas production. These wells usually produce about 40 gal of water per million cubic feet of gas and the gas contains from 0.1 pct to 2 pct carbon dioxide. In the operation of this type of well, the operators soon noted severe internal corrosion of the pipe carrying the production. In some instances the dl tubing has been found to be corroded to perforation in eight months. The high well head pressures of 2500 to 8000 psi makes any weakening of the well equipment by corrosion extremely hazardous. Bursting of the well equipment results in very expensive repair operations and may result in the loss of valuable production, loss of the costly well, or even loss of life. In November 1944, a gas-condensate well in a Gulf Coast field producing from 9500 ft showed a tubing leak. The well was "killed" by filling it with mud through the tubing, and then the tubing was pulled. Corrosion was found to have caused several perforations in the tubing, Fig I. While the mud was being circulated to kill the well, a high pressure jet from the corroded hole in the tubing perforated the casing and damaged the well to the extent that the cost of repairs amounted to $75,000. In November 1944, another gas-con-densate well in a Gulf Coast field producing from 11,400 ft showed tubing failure. This well had been producing an average of 2,500,000 cu ft of gas daily for two years. In the workover of this well, it was found that a hole one inch in diameter had corroded through the tubing and that corrosion had reduced the wall of the tubing to less than half the standard thickness over large areas of the interior of the tubing. It was found that corrosion had also caused two leaks in the casing. After four months spent in an attempted workover failed to make the well safe for further production, the well was plugged and abandoned at a total loss of $300,000,00.

Jan 1, 1948

By P. L. Menaul, P. P. Spafford

This paper discusses the most dangerous form of corrosion encountered in condensate-well oil production, the discovery of the agent causing this corrosion and the remedial chemical treatment proved effective by field use. The injection of ammonium hydroxide, even as little as one quart per day, has proved effective in preventing gas-condensate well corrosion. The injection of "Bone oil" is applied to wells producing brines containing calcium and magnesium salts. Introduction The severe corrosion of equipment in high pressure gas condensate wells has been a problem for several years and numerous papers have been presented on the subject. The term "gas condensate" or "distillate well" is applied to a distinct variety of hydrocarbon producing well, the characteristics of these wells being high bottom-hole (formation) pressures and temperatures and high gas production. These wells usually produce about 40 gal of water per million cubic feet of gas and the gas contains from 0.1 pct to 2 pct carbon dioxide. In the operation of this type of well, the operators soon noted severe internal corrosion of the pipe carrying the production. In some instances the dl tubing has been found to be corroded to perforation in eight months. The high well head pressures of 2500 to 8000 psi makes any weakening of the well equipment by corrosion extremely hazardous. Bursting of the well equipment results in very expensive repair operations and may result in the loss of valuable production, loss of the costly well, or even loss of life. In November 1944, a gas-condensate well in a Gulf Coast field producing from 9500 ft showed a tubing leak. The well was "killed" by filling it with mud through the tubing, and then the tubing was pulled. Corrosion was found to have caused several perforations in the tubing, Fig I. While the mud was being circulated to kill the well, a high pressure jet from the corroded hole in the tubing perforated the casing and damaged the well to the extent that the cost of repairs amounted to $75,000. In November 1944, another gas-con-densate well in a Gulf Coast field producing from 11,400 ft showed tubing failure. This well had been producing an average of 2,500,000 cu ft of gas daily for two years. In the workover of this well, it was found that a hole one inch in diameter had corroded through the tubing and that corrosion had reduced the wall of the tubing to less than half the standard thickness over large areas of the interior of the tubing. It was found that corrosion had also caused two leaks in the casing. After four months spent in an attempted workover failed to make the well safe for further production, the well was plugged and abandoned at a total loss of $300,000,00.

Jan 1, 1948

OFFICERS OF THE WOMAN'S AUXILIARY AIME President-Mrs Robert D Coombs, 375 Paramus Road, Paramus, N J First Vice-President-Mrs W McG Peirce, Troy Court 73 F, New England Avenue, Sum¬mit, N J Second Vice-President-Mrs Andrew E Beer, Richardson Avenue, Sea Cliff, Long Island, N Y Third Vice-President-Mrs Ira T Hook, 494 Norton Parkway, New Haven, Conn Fourth Vice-President-Mrs John R Kenney, 427 W Wrightwood Avenue, Chicago 14, Ill Fifth Vice-President-Mrs Alfonso Ballon, Montero Rosas 115, Barranco, Lima, Peru Recording Secretary-Mrs Arnold H Miller, 601 West 115th St, New York 25, N Y Assistant Recording Secretary-Mrs R J Mechin, 66 East 79th Street, New York 21, N Y Corresponding Secretary-Mrs Theodore Nagel, 76 Remsen St, Brooklyn 1, N Y Treasurer-Mrs Robert W Rowen, 116 East 68th St, New York 21, N Y Assistant Treasurer-Mrs Samuel H Dolbear, 11 Broadway, New York 4, N Y Assistant Treasurer-Mrs H A Kursell, 12 Murray Hill Road, Scarsdale, N Y

Jan 1, 1956

By Hsun Hu, R. S. Cline

The effect of rate of deformation on texture formatiotz has been studied with cube-oriented single crystals of 3 pct Si-Fe, compressed 80 pct at two widely different rates. Compression at a low rate (crosshead speed, 0.1 ipm) produces large orienta-tional changes and coarse deformation bands, whereas little change in orientation is observed, particularly at the surface of the crystal, when compressed at a high rate (impact velocity, -500 ips). Thin plates of mechanical twins are produced at the high rate, but their contribution to the deformation texture is practically negligible. The crystal deformed at a high rate has a lower hardness and a more uniform dislocation structure and is morc resistant to recrystallization. There is also a dilference in the recrystallization texture between the slowly and rapidly compressed crystals. These results indicate that plastic flow is less "turbulent" at high strain rates than at low strain ratcs. THE behavior of metals under high-speed deformation has been the subject of wide study in the past decade. Most of these works were concerned with mechanical properties during testing at high rates of loading, the resulting structures, and the theoretical aspects of the observed phenomena. The present status of knowledge and research activities in this field has been documented in recent publications.17' There is, however, very little information available in the literature concerning the effect of high-speed deformation on the texture formation in metals. The possibility of an effect of rate of deformation on texture is suggested by the microstructural differences observed between normally and very rapidly deformed samples. Aside from the strong tendency for twinning (and phase transformation in certain metals) in high-speed deformation, the slip-line patterns and the dislocation configurations show marked differences as a result of large differences in the strain rates. For instance, in mild steel in static and dynamic compression, Campbell and co-worker3,4 observed that coarse slip occurred on several systems in specimens deformed at normal strain rates, whereas specimens deformed rapidly showed only fine slip on fewer systems, the slip-line pattern being very similar to that in specimens deformed at low temperatures and at normal strain rates. The absence of multiple slip was also noticed by Dieter5 in shock-loaded nickel. The dislocation configuration in an iron shock loaded at 70 kbar pressure was shown by Leslie et al.6 to be similar to that produced by light rolling at low temperature—the dislocation lines were mostly straight and uniformly distributed. These observations suggest that the mode of deformation at high strain rates is notably different from that at low strain rates. Consequently, the nature and the extent of lattice reori-entation during deformation should also be different. This investigation was undertaken to test this idea. MATERIAL AND METHOD The remaining part of a single-crystal ingot of a 3 pct Si-Fe alloy,* prepared for an earlier investi- gation,1 was used in the present studies. Specimens 9/16 in. square and 0.365 in. thick were cut from this ingot with (001) planes parallel to the square surfaces, and the [loo] and 1010] directions parallel to the edges of the specimen, within ±1 deg. These machined crystals were etched to remove distorted metal, and annealed at 1300°C for 24 hr in a purified helium atmosphere. The annealed crystals had a hardness of 161 Dph. The crystal orientation was rechecked with X-ray back-reflection techniques. In high-strain rate experiments the crystal was compressed in a Dynapak machine to approximately 80 pct reduction in thickness (from 0.360 to 0.070 in. with an impact velocity of -500 ips). Thus, the duration of loading was approximately 6x 10-4 sec, and the average strain rate was about 103 sec-1. As a result of this rapid, severe deformation, the specimen became a roughly circular thin disc. The original shape of the crystal, however, could still be recognized by a diffusely outlined square area in the center of the disc. For compression at a low speed, the crystal was deformed in a universal testing machine at a rate of crosshead movement of 0.1 ipm. Compared with

Jan 1, 1965

By Lawrence Adler

In-situ rock has well-recognized rupture and yielding responses. Attention is called to an intermediate response, granulation, which consists of an evenly distributed, small-scale crumbling accompanied by swelling. Granulation results in a negative slope for the inelastic portion of the stress-strain curve as successive interlocks are destroyed, and the load-carrying capacity of the material is reduced. Volumetric swelling with softening also takes place. The prerequisites for such a response are moderate confinement and a uniformly distributed defect pattern. Since rock masses, as well as rock as an intact material, have such patterns in their jointing and texture, respectively, granulation is characteristic of them. The presence of granulation can be demonstrated for a very wide scale, ranging from laboratory testing to regional geologic phenomena. The response of an engineered structure is considered in detail. Granulation appears to be dependent upon internal moments, the formation of which can be controlled by engineering design. The practical implications of such control can be significant in optimizing underground instability and in improving excavation techniques. Rock is usually considered to behave inelastically under high load, by fracturing as a brittle material, or by yielding as a ductile material, ignoring time dependency. These responses, which are characteristic of metallic behavior, appear idealized in Fig. 1, where linear-elasticity approximates the initial behavior. However, another major deformation mechanism peculiar to rock has long been recognized in geology, the granulation of an interlocked material. Granulation consists of a uniformly distributed fracturing and crumbling of the material, accompanied by swelling and softening. Predictably, the associated inelastic portion of the load-deformation curve has a negative slope,

Jan 1, 1971

By R. D. Reiswig, J. M. Dickinson

The 0s-Ir equilibrium diagram was determined. The diagram is of the simple peritectic type, with a peritectic temperature of about 2660°C. The solid miscibility gap is narrower than previously reported, the nearly vertical solvus lines occurring at about 42 and 63 wt pct 0s. Widmanstaetten figures resembling martensite in some of the two-phase alloys account for a previously suspected transformation. In view of the long history of use of such alloys, it is surprising that the 0s-Ir equilibrium diagram has not yet been completely determined. The boundaries of the miscibility gap in this system have been estimated to be between 24 and 39 wt pct 0s and 79 and 100 wt pct OS. It has been predicted3 that alloys of ruthenium, osmium, and rhenium with the fcc platinum metals should solidify peritectically in their two-phase regions. The metallographic examination of natural osmiridium alloys has been said4 to indicate, by the presence of a martensitic structure, the existence of a transformation or a phase separation. On the basis of superconducting transition temperature measurements, a 70 at. pct 0s alloy was found5 to be two-phase prior to annealing. EXPERIMENTAL The elemental components used in this work were obtained from several suppliers as sponge. The purities, stated by each supplier to be in excess of 99.8 pct, were confirmed in each case by a semiquantitative spectrographic analysis. The pure components were premelted in an inert-gas tungsten arc furnace with the evolution of some fume, crushed, and pickled for use as alloy melting stock. Upon arc melting to the final compositions, no fume evolution was observed. Because weight losses of the order of 15 mg or less were observed in preparing alloy buttons weighing 15 g, "synthetic analyses" were used in determining the compositions of the alloys. Alloys used in this investigation contained 15, 20, 33, 40, 42, 43, 45, 50, 55, 60, 63, 64, 66, 70, 79, and 80 wt pct 0s. Heat treatments of the alloy buttons and pieces thereof were performed in a previously described6 tungsten tube furnace under pressures of 105 torr or less. It was found that homogenization treatments on the specimens were essential to remove the severe coring which was present, a 3-hr treatment above 2300°C removing all the metallographi-cally visible evidence of coring. Following the various heat treatments, the specimens were "vacuum-quenched" by melting a tungsten fuse wire and allowing them to drop onto a water-cooled copper plate. In a few instances, specimens were quenched into molten tin for comparison, but no difference was apparent. Vacuum-quenched specimens cooled from 2400°C to below a red heat in less than 60 sec. Typical equilibration times varied from 3 hr above 2300°C to 88 hr near 1100°C. The utilization of successively longer equilibration times and the approach to equilibrium from both directions indicated that the times used were sufficient to give a close approach to true equilibrium. Heat-treatment temperatures were measured with a calibrated Leeds and Northrup optical pyrometer through a 0.120-in. lateral sight hole in the tungsten heater tube. It was known that the assumption of black-body conditions inside the 1-in.-diam by 10-in.-long tube was unwarranted. The empirical results of work with thermocouples and melting

Jan 1, 1964

By H. I. Aaronson, H. A. Domian

The self-diffusivity of Ag10 has been measured as a function of temperature and composition in AgMg. a CsCl-type intermetallic compound with a substitutional defect structure on both sides of the stoichiometric (50 at. pct Mg) composition. These measurements show that In D increases linearly, and both In Do and Q decrease linearly with deviation from stoichiometry. The slopes of these lines are significantly steeper in magnesium-rich alloys. Equations for the variation of Q with composition have been derived by application of the theory of random walk processes on the assumption that diffusion in compounds of this type takes place by the six-jump cycle mechanism of Huntington, Elcock, and McCombie. The favorable agreement obtained with experiment furnishes fresh support for the correctness of this assumption. A principal result of this treatment is that. although the concentration of vacancies is considerably higher in the silver sublattice than in the magnesium sublattice, the acfivation energies for movement of the magnesium sublattice vacancies are so much lower that these vacancies are responsible for effectively all diffusion of silver in this compound. A tendency for vacancies of both types to be kinetically bound to wrong atoms is also noted. THIS study was undertaken to examine the influence of substitutional defects upon self-diffusion in an intermetallic compound, AgMg, with a CsCl-type crystal structure. The CsCl structure is exception- ally simple. At the equiatomic or stoichiometric composition in a binary alloy, it consists of two interpenetrating simple cubic sublattices, each of which is exclusively populated by the atoms of one species. When atomic size and other factors are favorable, deviations from stoichiometry can be entirely accommodated by the substitution of atoms of the species present in excess of 50 at. pct on the sublattice of the other species on a one-for-one basis. Under this condition, the only vacancies present are those formed by thermal activation. The excess atoms thus incorporated into the sublattice of the minority species may be considered as substitutional defects in this sublattice. Several X-ray studies have shown that the defect structure of AgMg is entirely of the substitutional type on both sides of the stoichiometric composition.1"3 The thermodynamic investigation of Kachi indicates that, aside from a low level of thermal disorder and these constitutional defects, order is maintained to the solidus temperature. This compound is therefore a particularly useful vehicle for a study of the influence of substitutional defects upon diffusion kinetics. Other advantages of AgMg for this purpose include: the broad composition region, as much as approximately 10 at. pct on either side of the stoichiometric (50 at. pct Mg), in which the compound is stable; the comparatively low temperature range of the solidus (820°C and below),5 making diffusion anneals near this range experimentally convenient; the reasonably good machinability of the compound, permitting utilization of the standard sectioning method of radiotracer analysis; and the availability of a good tracer, A for one of the constituent species. While this investigation was in progress, Hagel and westbrooks reported data on the self-diffusion

Jan 1, 1964

By A. A. Scheil, S. I. Hoyt

In technological studies on steel considerable emphasis has been placed on the identification of the foreign inclusions, testimony of which is adequately given in the metallographic literature covering methods for their identification. The outstanding accomplishment in this field is the scheme devised by Campbell, Comstock and Wohrman for identifying various oxides, sulfides, silicates and other constituents by systematic etching tests and microscopic examination.' The time involved in carrying out this procedure has led to attempts to secure quicker methods, or at least to shorten the time required to secure essential information. An example of this is the use of dark field illuminatin,2 but when this was tried out by the authors it was found that cavities and pits on the polished surface appeared bright on a dark field and could not be distinguished from small glassy inclusions. Still another means is the Leitz Ultropak, an instrument equipped with optical units for the illumination of the specimen by reflected light to secure an effect similar to dark field illumination. The structures are made visible in exceedingly sharp details by utilizing the inherent properties of the samples, such as refractive index, absorption coefficients and reflection powers. We have had no experience with the Ultropak, but a recent paper by Benedicks and Löfquist3 describes methods for determining the refractive index of (Fe, Mn) O and MnS by the use of this equipment. Presumably this method would be subject to about the same limitations as dark field illumination, though the, feature added by Benedicks and Löfquist appears to offer great promise in inclusion identification.

Jan 1, 1935

By A. A. Scheil, S. I. Hoyt

In technological studies on steel considerable emphasis has been placed on the identification of the foreign inclusions, testimony of which is adequately given in the metallographic literature covering methods for their identification. The outstanding accomplishment in this field is the scheme devised by Campbell, Comstock and Wohrman for identifying various oxides, sulfides, silicates and other constituents by systematic etching tests and microscopic examination.' The time involved in carrying out this procedure has led to attempts to secure quicker methods, or at least to shorten the time required to secure essential information. An example of this is the use of dark field illuminatin,2 but when this was tried out by the authors it was found that cavities and pits on the polished surface appeared bright on a dark field and could not be distinguished from small glassy inclusions. Still another means is the Leitz Ultropak, an instrument equipped with optical units for the illumination of the specimen by reflected light to secure an effect similar to dark field illumination. The structures are made visible in exceedingly sharp details by utilizing the inherent properties of the samples, such as refractive index, absorption coefficients and reflection powers. We have had no experience with the Ultropak, but a recent paper by Benedicks and Löfquist3 describes methods for determining the refractive index of (Fe, Mn) O and MnS by the use of this equipment. Presumably this method would be subject to about the same limitations as dark field illumination, though the, feature added by Benedicks and Löfquist appears to offer great promise in inclusion identification.

Jan 1, 1935

By G. W. Brock

Experiments in the form of aging of overstrained tension specimens and elevated temperature tension testing, have been carried out on recrystallized arc-cast molybdenum. The aging behavior of molybdenum was found to be strongly dependent on the degree of plastic strain present in the lattice: the reason for this being the low solid solubility for the common interstitial elements in molybdenum. GEORGE W. BROCK, formerly Research Associate, Department of Theoretical and Applied Mechanics, University of Illinois, Urbana, III., is Research Associate, Department of Engineering Sciences, IBM Research Center, Yorktown Heights, N. Y. Manuscript submitted January 19, 1961. IMD THE term strain aging is familiar in connection with the recovery of the yield point in mild steel after tensile overstraining, and there are other instances where it is known to exert an appreciable effect on mechanical properties. For example, steel exhibits a greater tensile strength at mildly elevated temperatures than at room temperature and serrated stress-strain flow curves occur under certain conditions. It has been known for a number of years that the phenomenon of strain aging is directly connected with the presence of carbon and nitrogen in the lattice; and extremely small amounts of either element are sufficient to produce the effect. In this study, the aging behavior of overstrained tensile specimens of recrystallized molybdenum has

Jan 1, 1962