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By C. T. Eddy, R. W. Drier

The conductivity of copper wire is of prime importance to the electrical industry and consequently to the copper refiner and wire manufacturer. Annealed copper wire has a higher conductivity than hard-drawn wire, but, on the other hand, its tensile strength is lower. In an attempt to explain the reasons for these changes in properry. or at least to study the conditions existing in these two types of copper wire, the experiments described here were carried on in the Department of Metallurgy of the Michigan College of Mining and Technology This is only a partial and preliminary report on some of the work done to date on a research program of which the object is an intensive study of copper. It is offered with the hope that, though it is not an exposition of the most rigorous of conclusions, the general trend of inferences which may be drawn will be of value and interest. Effect of Direction of Drawing In 1928 some work was done on hard-drawn copper wires to determine whether wire drawn in a continuous machine (that is, all in one direction) would have a different structure from wire that had a reversal in direction at some stage of the drawing process. The diffraction spectra obtained indicated that as the position of the wire rayed approached the core, a preferential crystal orientation existed, and that the closer to the core the more preferred was the orientation. The data obtained partly corroborated the work done by Schmidt and Wassermanl and by Clark.2 Samples Used in Following Investigation The samples selected for use in both the diffraction work and the resistivity measurements were taken from Nos. 6, 8, 10 and 12 gage

Jan 1, 1930

By Earle E. Schumacher, W. C. Ellis, John F. Eckel

Copper-calcium alloys are of interest as materials for use in deoxidized conductors of high conductivity. That calcium is effective in deoxidizing and degasifying copper is well known. Brandenberg and Wiensl have described the use of calcium in the casting of sound copper and state that the deoxidation can be carried out without difficulty. The castings that they prepared were sound and sufficiently ductile to permit wire drawing. Pratt,2 in British Patent No. 1699 (1907), has claimed the use of calcium for the deoxidation and degasification of copper. Masing3

Jan 1, 1930

By C. H. Mathewson, Kent R. Van Horn

Copper and the copper-base solid solutions readily form twin crystals when plastically deformed at a suitably elevated temperature or annealed after cold deformation. In fact, no feature of the microstructure of these materials is more prominent or characteristic than these straight-sided bands or simple lines of division which sometimes come from groups of thin polysynthetic lamellae, penetrating part way or wholly through the parent grain substance, but often divide the grain into a few or perhaps only two crystallographically related parts. Nearly always the bands as seen in the usual microscopic examination of a specimen come into vivid contrast with the adjacent crystalline material owing to the inherent difference in orientation. Bands which under special conditions of orientation cannot be seen with vertically incident light are often visible under oblique illumination and, when this fails, contrasting effects usually may be obtained by using polarized light. There is no longer any doubt that these synthetic banded structures obtained in the ordinary course of working and annealing are due to twinning of the spinel type which was observed long ago in a number of metals crystallizing in the isometric system.' It has been customary in metallurgical literature to designate these synthetic twins, which grow into prominence during an annealing process, as "annealing twins" without regard to the actual mode of their formation, which is, indeed, obscure and with scant recognition of the fact that prior deformation is essential, no twins having been observed in metal of known unstrained history. This is questionable; especially in view of the fact that in a number of metals and minerals, reorientation into the twin configuration is known to occur as a result of a simple shearing mechanism along the recognized twinning planes and the

Jan 1, 1930

By Daniel R. Hull, H. F. Silliman, Earl W. Palmer

The brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6¾ in. wide by I in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breakdown rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause—however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By H. F. Silliman, Daniel R. Hull, Earl W. Palmer

The brass-rolling industry has not had a great deal of experience with antimony in its product. There have been some recent excursions with antimony as a corrosion inhibitor in tubes, but in sheet brass it has been regarded with apprehension and generally avoided. This is not to say that contaminations have never occurred, and probably a great many brass mill men have had their own ideas on the effect of such contamination. Our own views were based upon certain experiences some years ago with strip castings that split lengthwise in the early stages of rolling. The nature of this splitting is shown in Fig. I, from a photograph taken in 1922 as a record of 20 bars of 65-35 common brass made with an antimonial brand of copper. These bars were cast 6¾ in. wide by I in. thick by 45 in. long. In the first pass through the rolls, 19 of the 20 split lengthwise throughout their length, while each half curved outward in a wide arc as it emerged from the rolls. In those days, if splitting was not a frequent occurrence, it was not unfamiliar. One can recall periods of short duration when large amounts of common brass would behave in this way. There was nothing imaginary about these spells. The affected metal would split lengthwise in the breakdown rolls, and no maneuvering of mill practice made any difference. The condition would descend like a plague, demoralize the mill for several days, and disappear. It is doubtful if anyone knew the cause—however many explanations may have been current. In 1921 a quantity of split brass was traced to the use of fired small-arms

Jan 1, 1943

By A. A. Smith, J. S. Smart

THe elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses. When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range o to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorilv determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing 2nd oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B, and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold. The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300' and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type. All samples were quenched from the annealing temperature in 10 per cent H²S04 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.' Effect of Silver Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By A. A. Smith, J. S. Smart

THe elements silver, cadmium, tin, antimony and tellurium either are found as impurities in commercial coppers or are intentionally added to produce coppers for special uses. When present in small quantities, each of these metals exerts a significant effect on the properties of copper, but despite considerable experience and investigation much remains to be learned about their specific behavior. The presence of extraneous elements, particularly oxygen, complicates the study of individual additions of impurities in the range o to 0.05 per cent, and the use of high-purity copper has been found extremely helpful in circumventing these difficulties. It has also been found that individual behavior can be satisfactorilv determined from measurements of two commercially important properties, conductivity and softening temperature, according to methods that have been described previously.1,2 Data of this type, obtained in the course of a general investigation of the effects of impurities on the properties of both oxygen-bearing 2nd oxygen-free copper are presented herewith. All samples except those containing cadmium were prepared as 3/8-in. continuously cast oxygen-free rod from pure copper and weighed amounts of a similarly synthesized master alloy. Composition was checked by chemical methods, which in every case verified the calculated analyses. Test wires were cold-drawn one B, and S. number per pass on a string-up machine using four 30-min. 600°C. anneals at 0.3125, 0.257, 0.204 and 0.162 in. and a final cold reduction of 75 per cent to 0.081 in. Some oxygen-bearing samples were produced directly from the 3/8-in. oxygen-free rods by diffusion from a surface scale at 850°C. and drawn to size as listed above, but most of the alloys were remelted in pure graphite and cast through air into a I-in. round mold. The slugs were then hot-rolled to 5/16 in., drawn to 0.162 in., annealed as listed above, and drawn to 0.081 inch. Conductivity wires were annealed for I hr. at 100°C. intervals between 300' and 800°F., using a hydrogen atmosphere for oxygen-free samples and purified nitrogen for the oxygen-bearing type. All samples were quenched from the annealing temperature in 10 per cent H²S04 and conductivity was measured on a Hoopes bridge that had been checked against a Kelvin bridge. The softening temperatures represent the half-hard stage of the annealing curve as determined by a standard procedure.' Effect of Silver Numerous excellent studies of the argentiferous coppers are found in the literature, and these have been adequately

Jan 1, 1943

By G. P. de Forest, G. O. Hiers

The object of the experiments reported in this paper is to determine the eutectic composition of copper and tin and to determine the location of the part of the liquidus line immediately above the eutectic composition in copper. Three methods were used in the investigation: (1) the method of dissolving copper in a bath of molten tin at constant temperature, with the idea that when the bath was saturated with copper its copper content, by analysis, together with the temperature at which the saturation took place would locate a point on the liquidus line; (2) the method of the differential cooling curves, and (3) the method of microscopic examination. This paper is principally concerned with the results of the last two methods mentioned. The results of the first method, that of dissolving copper in molten tin, did not agree with the results of Miller,' by the same method, nor with the results of other investigators by other methods, nor yet with the results of the cooling-curve experiments and microscopic examination reported here. Solution of Copper in Molten Tin To determine the amount of copper that would be dissolved by molten tin at a given constant temperature the apparatus shown in Fig. 1 was used. It consists of a cast-iron pot a, 6 in. deep and 8 in. dia., well cleaned inside and dressed with graphite. This pot, which holds 15 lb. of tin, g, rests on a hot plate b with resistance winding c. The thermocouple d leads to a Wilson-Maeulen temperature regulator for maintaining the temperahre at the heating coils at a fixed temperature to within ±5°C. There is a shallow bath of solder e on the top of the hot plate to improve the thermal contact between the plate and the pot. An insulating jacket f of asbestos prevents the irregular radiation of heat from the apparatus. The copper stirrer h slowly rotates in, and is dissolved by the bath of molten tin g. This bath is protected from excessive oxidation by a layer of charcoal j. The stirrer h is fixed to the lower end of the iron tube k, which is so mounted that it can be driven by a motor with reducing gear. The temperature of the bath is indicated

Jan 1, 1930

By Cyril Stanley Smith

BeTa brass (consisting of approximately equal atomic proportions of copper and zinc) exists as a random solid solution at high temperatures, hut at low temperature< an ordered structure is stable, with the copper and zinc atoms occupying alternate sites on the body-centered-cubic lattice. On cooling, ordering commences at a temperature of 450° to 470°C., depending on the composition. The degree of ordering progressively increases at lower temperatures until it becomes virtually complete at about 100°C. The electrical resistivity of the alloy illustrates the changes clearly (Fig. I). This type of reaction has been a favored subject for study by physicists. An excellent summary of the theory is to be found in a paper by F. C. Nix and W. Shock1ey.l All published data on electrical conductivity, specific heat and other properties agree in indicating that the ordering reaction in beta brass takes place so rapidly that it cannot be prevented or even retarded by quenching&apos; With most ordered alloys, cold-working induces disorder and

Jan 1, 1943

By Cyril Stanley Smith

BeTa brass (consisting of approximately equal atomic proportions of copper and zinc) exists as a random solid solution at high temperatures, hut at low temperature< an ordered structure is stable, with the copper and zinc atoms occupying alternate sites on the body-centered-cubic lattice. On cooling, ordering commences at a temperature of 450° to 470°C., depending on the composition. The degree of ordering progressively increases at lower temperatures until it becomes virtually complete at about 100°C. The electrical resistivity of the alloy illustrates the changes clearly (Fig. I). This type of reaction has been a favored subject for study by physicists. An excellent summary of the theory is to be found in a paper by F. C. Nix and W. Shock1ey.l All published data on electrical conductivity, specific heat and other properties agree in indicating that the ordering reaction in beta brass takes place so rapidly that it cannot be prevented or even retarded by quenching&apos; With most ordered alloys, cold-working induces disorder and

Jan 1, 1943

By Clarence Zener

The internal friction of nonferrous metals vibrating at low stress amplitudes has so far always been successfully interpreted in terms of inhomogeneities of one sort or another. Examples are the fluctuation of stress across a specimen vibrating transversely,1,2,3 the stress inhomogeneities due to the elastic anisotropy and partial random orientation of the individual crystallites, localized weak regions introduced by cold-working,6&apos;7 grain boundaries and possibly twinning planes.8&apos;9 Perfect single crystals are, by definition, homogeneous. Actual single crystals usually, perhaps always, contains some imperfections. The present investigation was undertaken to determine whether the internal friction of single crystals may likewise be attributed to inhomogeneities. This study was made possible through the gift of a large single crystal of 70-30 alpha brass by H. L. Burghoff, of the Chase Brass and Copper Co. The specimen, 3.i in. in diameter and 10 in. long, was similar to samples previously described by Mr. Burghoff. Experimental Method The experimental method used has previously been described in institute papers.5&apos;6&apos;9 The measure of internal friction adopted here, I/Q, is X the logarithmic decre- ment, a measure used by some writers, and is also X the specific damping capacity, a measure used by other writers. In all measurements the stress level was kept so low that the measurements were independent of stress level. In all measurements in which the temperature was varied, observations were made as the specimen slowly cooled from its highest temperature. The specimen was vibrated transversely. Observations were made at the fundamental frequency and at the first overtone, of about 620 and 1710 cycles per second, respectively. No attempt was made to avoid acoustical losses. Experimental Results The specimen was annealed for several hours at 450°C. The temperature dependence of the internal friction was then determined from room temperature to 400°C. As shown in Fig. I, the internal friction increased by only a factor of 2 from room temperature to 300°C., then by a factor of 100 during the next Ioo° interval. These measurements are consistent with the view that the observed internal friction is the superposition of two distinct parts. One, dominant at room temperature, is nearly independent of temperature. This part may be accounted for by acoustical losses and by transverse thermal currents. It was not further investigated. The second part, when plotted in the manner of Fig. I, lies upon a straight line. Therefore it has a heat of activation H; i.e., it varies with temperature as Internal friction e-H/RT [I]

Jan 1, 1943

By Clarence Zener

The internal friction of nonferrous metals vibrating at low stress amplitudes has so far always been successfully interpreted in terms of inhomogeneities of one sort or another. Examples are the fluctuation of stress across a specimen vibrating transversely,1,2,3 the stress inhomogeneities due to the elastic anisotropy and partial random orientation of the individual crystallites, localized weak regions introduced by cold-working,6&apos;7 grain boundaries and possibly twinning planes.8&apos;9 Perfect single crystals are, by definition, homogeneous. Actual single crystals usually, perhaps always, contains some imperfections. The present investigation was undertaken to determine whether the internal friction of single crystals may likewise be attributed to inhomogeneities. This study was made possible through the gift of a large single crystal of 70-30 alpha brass by H. L. Burghoff, of the Chase Brass and Copper Co. The specimen, 3.i in. in diameter and 10 in. long, was similar to samples previously described by Mr. Burghoff. Experimental Method The experimental method used has previously been described in institute papers.5&apos;6&apos;9 The measure of internal friction adopted here, I/Q, is X the logarithmic decre- ment, a measure used by some writers, and is also X the specific damping capacity, a measure used by other writers. In all measurements the stress level was kept so low that the measurements were independent of stress level. In all measurements in which the temperature was varied, observations were made as the specimen slowly cooled from its highest temperature. The specimen was vibrated transversely. Observations were made at the fundamental frequency and at the first overtone, of about 620 and 1710 cycles per second, respectively. No attempt was made to avoid acoustical losses. Experimental Results The specimen was annealed for several hours at 450°C. The temperature dependence of the internal friction was then determined from room temperature to 400°C. As shown in Fig. I, the internal friction increased by only a factor of 2 from room temperature to 300°C., then by a factor of 100 during the next Ioo° interval. These measurements are consistent with the view that the observed internal friction is the superposition of two distinct parts. One, dominant at room temperature, is nearly independent of temperature. This part may be accounted for by acoustical losses and by transverse thermal currents. It was not further investigated. The second part, when plotted in the manner of Fig. I, lies upon a straight line. Therefore it has a heat of activation H; i.e., it varies with temperature as Internal friction e-H/RT [I]

Jan 1, 1943

By Charles S. Barrett, Robert F. Mehl

It is generally understood by workers in the field of the crystal structure of metallic alloys that terminal solid solutions are of two types, the substitutional and the interstitial. In reviewing the literature, the work of Weissl on the crystal structure of the alpha copper-tin alloys was encountered, in which a new type of terminal solid solution was proposed. In brief, Weiss&apos; findings showed that the density of the alloys calculated from the side of the unit face-centered cube on the assumption of simple substitution—that is, with four atoms to the unit face-centered cell—was much higher than the density measured directly. It was suggested that the assumption of four atoms to the unit cube is not valid for these alloys, and that each unit cube contained less than four atoms; in other words, that one tin atom replaces more than one copper atom, leaving some atomic positions unoccupied. Such a structure, if verified, would have far-reaching significance in the study of the crystal structure of metallic alloys. It would indicate a complexity in terminal solid solutions not hitherto suspected and might encourage work leading to the discovery of other alloys of the same type, and perhaps to types intermediate between it and the two recognized types. It is of importance, therefore, to reinvestigate these alloys with respect to the type of solid-solution structure obtaining therein. Materials and Experimental Method The alloys were prepared from electrolytic copper cut directly from the cathode and the high-purity tin furnished by the U. S. Bureau of Standards for the calibration of thermocouples. No analyses for impurities of these materials or of the finished alloys were made, since such impurities as might be present could have only a wholly inappreciable effect upon the data obtained and the conclusions drawn. The alloys were made by melting the weighed copper charge in a graphite crucible under a KCl-LiC1 flux with later additions of NaC1, using induction heating. When the copper was melted the weighed portions of tin were

Jan 1, 1930

By Cyril Stanley Smith

Although not of the same importance as electrical conductivity, the capacity for conducting heat is nevertheless a very important property of metals and alloys. A knowledge of thermal conductivity is of value in selecting alloys for many purposes and in the calculation of the efficiency of apparatus which is being designed. Unfortunately, the determination of thermal conductivity is extremely slow and tedious, consequently few data have been obtained. A further reason for the lack of information is that there has long been an impression that the thermal conductivity of an alloy is directly proportional to the electrical cónductivity and that it can therefore be calculated from the latter. The Wiedmann-Franz-Lorenz law of constant ratio of the two conductivities holds with a considerable degree of precision for all the pure metals, but appreciable deviations occur in certain alloys—particularly those containing nickel—and it seems difficult to predict exactly what the ratio will be. Therefore direct determinations of thermal conductivity should be made whenever the results are needed with any accuracy. This research is intended eventually to cover all the alloys of copper that are of commercial importance, including the binary alloys of copper with zinc, tin, aluminum, nickel, silicon, manganese, cadmium and phosphorus, and the ternary alloys copper-nickel-zinc, copper-nickel-silicon, copper-manganese-silicon, copper-zinc-tin, etc. Most of these alloys are customarily used in the wrought condition and therefore were tested in the form of annealed rods. A limited number of sand castings were also obtained and examined. This paper contains a complete review of all the previous work that has been done on copper alloys, and includes a detailed description of the apparatus and method of procedure used in the present research, together with the new results obtained on the copper-zinc series, which is the only one completed at the present time. Subsequent papers describing the other alloys will contain the experimental results and discussion only. Previous Work Copper The conductivity of copper has been studied by many observers since the pioneer work of Wiedemann in 1859. The majority of these measure-

Jan 1, 1930

By L. L. Wyman

Previous studies1 by the writer dealing with the embrittlement of copper have been concerned with the behavior of various pure and deoxidized coppers when exposed to an oxidation-reduction cycle, and the consequent evaluation of these materials on the basis of their resistance to this action. No attention was devoted to the variations in penetration of embrittlement with time, when these copper materials are exposed to a strong reducing gas, such as hydrogen, nor to the variations in oxygen penetration, with time and temperature, into the "pure" coppers. The cause of the embrittlement is the reduction of the oxygen in the copper by the hot reducing gas, so that a consideration of time, temperature, the occurrence of hydrogen and oxygen must be given. For the purpose of differentiating some of the involved factors, the present work may be divided into two separate series of experiments. The first of these deals with the oxidation of purified coppers under various conditions and then the subjection of these to a standard hydrogen treatment. The second series concerns the reduction, under different conditions, of tough-pitch coppers of several oxygen contents. The resulting data will give the rates of oxidation, and of reduction, for the materials involved. The first series of experiments will reveal how rapidly copper may become oxidized, while the second series will indicate how rapidly embrittlement will penetrate into an oxygen-containing copper when it is exposed to hydrogen at different temperatures. Materials For the purpose of determining these variables, three types of material were selected, to cover the extremes in the ranges of materials commercially obtainable. The first class of materials is represented by an oxygen-free copper, as well as the high-purity vacuum-melted copper2 used in previous work. These materials were selected to determine the variation of oxidation with time and temperature, by oxidizing these coppers under various combinations of these factors, and noting the effect as indicated by a

Jan 1, 1934

By L. L. Wyman

The resultant embrittlement caused by the exposure of oxygen-bearing copper when hot and exposed to reducing gases has been the subject of many studies.&apos; Little attention, however, has been given to the possible embrittling effects due to atmospheres or conditions that under some circumstances might be the source of a reducing gas. At rather infrequent intervals there occur reports of copper becoming embrittled during normal annealing cycles in commercial steam-atmos-phered furnaces such as customarily are used for this operation. As might be expected, several other factors exist—such as oil, dirt on the wire, or in the furnace, or metallic surface contacts—that might produce reducing gases and be the source of the trouble. However, in consideration of the statement made by Ruder,2 it would seem that under some conditions steam itself might prove to be the source of trouble. A consideration of the amount of the dissociation of water vapor up to temperatures of the melting point of copper shows that3 the amount of hydrogen that could come from this source is far too minute to account for any embrittlement. What such information does not tell is what will happen at the surface of copper when subjected to steam at elevated temperatures, for entirely different conditions may persist, which would account for Ruder&apos;s observation. Furthermore, there are no data as to what might happen at the surfaces of other materials present, the resultant of which might affect the condition of the copper present. For this reason, it was decided to make a series of experiments comparable to those previously conducted by the writer,&apos; which would clarify the effect of the steam on copper, and in copper in the presence of steel. Material The material used in these experiments was tough-pitch copper wire of rectangular cross section, about % in. thick, picked at random from the regular factory production of material used for windings, etc., in the electrical industry. Chemical analysis of this material gave the follow-

Jan 1, 1940

By L. L. Wyman

The resultant embrittlement caused by the exposure of oxygen-bearing copper when hot and exposed to reducing gases has been the subject of many studies.&apos; Little attention, however, has been given to the possible embrittling effects due to atmospheres or conditions that under some circumstances might be the source of a reducing gas. At rather infrequent intervals there occur reports of copper becoming embrittled during normal annealing cycles in commercial steam-atmos-phered furnaces such as customarily are used for this operation. As might be expected, several other factors exist—such as oil, dirt on the wire, or in the furnace, or metallic surface contacts—that might produce reducing gases and be the source of the trouble. However, in consideration of the statement made by Ruder,2 it would seem that under some conditions steam itself might prove to be the source of trouble. A consideration of the amount of the dissociation of water vapor up to temperatures of the melting point of copper shows that3 the amount of hydrogen that could come from this source is far too minute to account for any embrittlement. What such information does not tell is what will happen at the surface of copper when subjected to steam at elevated temperatures, for entirely different conditions may persist, which would account for Ruder&apos;s observation. Furthermore, there are no data as to what might happen at the surfaces of other materials present, the resultant of which might affect the condition of the copper present. For this reason, it was decided to make a series of experiments comparable to those previously conducted by the writer,&apos; which would clarify the effect of the steam on copper, and in copper in the presence of steel. Material The material used in these experiments was tough-pitch copper wire of rectangular cross section, about % in. thick, picked at random from the regular factory production of material used for windings, etc., in the electrical industry. Chemical analysis of this material gave the follow-

Jan 1, 1940

By J. L. Christie, W. R. Webster, R. S. Pratt

Since the delivery of our paper on Some Comparative Properties of Tough-pitch and Phosphorized Copper,1 a new brand known as "oxygen-free high-conductivity copper" (brand OFHC) has become available to consumers. It was thought desirable to make a comparison between the properties of this material and those of the materials covered by our original paper and its discussion. Preliminary tests had indicated some notable differences. A billet of oxygen-free high-conductivity copper was taken from regular production. A chemical analysis of the particular billet was not made, but the producer of the material has given as typical the analysis shown in Table 1. The

Jan 1, 1933

By L. L. Wyman

Since the presentation, by the writer, of the initial paper on the embrittlement of copper,1 the subject has been investigated further along two separate lines. The first series of investigations involves the "double-deoxidized" coppers, while the second series is devoted to single deoxidizers other than those used in the investigations reported upon last year. The object of these experiments is to develop a type of copper that will show the minimum of detrimental effects after having been exposed to alternate oxidation and reduction. The fabrication of this material necessitates the use of alternate oxidizing and reducing atmospheres, at temperatures ranging up to 900" C. Following this treatment it is essential that the soundness and strength of the copper be unimpaired, even in sections of only a few thousandths of an inch in thickness. Materials The ensuing report embodies three separate groups of materials, which may be classified as follows: 1. Double-deoxidized copper using silicon and calcium boride. 2. Copper deoxidized with calcium. 3. Double-deoxidized copper using constant calcium content (0.075 per cent) plus silicon, or calcium boride. Last year, T. S. Fuller, of the General Electric Research Laboratory, suggested that if a properly deoxidized copper had sufficient deoxidizer residual in the material, this excess material might increase the resistance of the copper to the oxidation reduction cycle. In consequence of this suggestion, two small lots of "double-deoxidized" copper were prepared. The first, lot A, was made by adding 0.03 per cent silicon as the deoxidizer, following this by an addition of 0.55 per cent calcium boride immediately before pouring. The second, lot B, contained the same ingredients, but these were added in the reverse manner. Inasmuch as these lots were tested separately from the materials about to be described, it must be borne in mind that the materials cannot be grouped together, and are not directly comparable.

Jan 1, 1933

By Arthur Phillips, Carl H. Samans

The study of anisotropy in metals has been greatly stimulated in recent years by the rapid development of X-ray methods for determining the crystallographic relationships of wrought and annealed materials. Prior to this time the knowledge regarding the directional properties of commercial alloys consisted almost exclusively of observations of a practical nature made during the fabrication of metal objects, supplemented by a limited number of mechanical tests on specimens cut at various angles to the direction of working. Such observations clearly indicate that the common methods of cold-working metals cause both a crystallographic and a mechanical fibering varying in character and degree according to the nature and extent of the deforming process. Even after annealing, following certain not too well known combinations of reductions and anneals, a preferred orientation may exist,, thereby constituting a residual fiber effect sufficiently pronounced to manifest directional properties. With the application of the X-ray the experimental horizon was extended chiefly because the study of anisotropic metals promised to offer direct and quantitative evidence regarding the involved mechanism of fragmentation and plastic flow. As a natural consequence the intensive studies in this direction have yielded a vast accumulation of data of ultimate potential value. Unfortunately, however, as is commonly the case in entering a virgin field of experimentation, many of the data cannot be molded into complete and coherent form because of the many unrelated conditions of the experimental projects. Again, the results of the study of single crystals have been rather naturally but at times indiscriminately applied to poly crystalline metals. Furthermore, sweeping statements have been made regarding the behavior during working and annealing of metals and alloys, entirely on the basis of similarity in lattice arrangement. There is abundant reason for believing that relatively small concentration variables, differences in magnitude and distribution of applied stresses, and the character of associated annealing treatments may in some cases greatly influence the mechanics of flow

Jan 1, 1933