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By J. M. Markowitz

The movement of hydrogen in two-phase Zircaloy-2 under the influence of a thermal gradient was studied in specimens of cylindrical geometry. A gross displacement of hydrogen toward the cooler regions of the specimen was observed with consequent copious precipitation of 6-ztrconium (ZrH) there. The kinetics of the diffusion are analyzed and discussed. X HE temperature-gradient redistribution of hydrogen in a-Zircaloy-2 has been treated both theoretically and experimentally Hydrogen moves toward the cold side of the temperature gradient until a steady state has been established; tendency for further hydrogen movement because of temperature differences is nullified by the tendency to move in the reverse direction because of the concentration gradient. The steady state condition is described by the equation in which iV is the concentration of hydrogen at a point in the specimen corresponding to absolute temperature T, R is the gas constant,k is a constant of integration, and Q is a parameter called the heat of transport, characteristic Of the particular system. The value of Q has been determined for hydrogen in Zircaloy-2 by several investigators, using Eq. [11. There is considerable variation in the results, the cause of which has not been resolved; reported values lie in the range 3 to 6 kcal per mole. The physical situation for two-phase thermal migration is much more complex. The -phase boundary for the solubility of hydrogen in Zircaloy-2 ranges from a concentration of 25 ppm at 200°C to a maximum of about 600 ppm at 550°C.4a Thus, if the concentration of hydrogen in Zircaloy-2 is sufficiently great (>600 ppm), the specimen will be entirely two-phase, consisting of a matrix of a-Zircaloy-2 surrounding particles of zirconium hydride. At time zero, with a temperature gradient imposed, the relative amounts of hydride and a-phase in each infinite-simally thin isothermal section of the specimen can be determined from the phase diagram by the lever rule. Moreover, the concentration of hydrogen in the matrix phase varies from point to point, following the a solubility line. Over most of this temperature range (<450°C) 6 phase, Fig. 3, has a constant concentration.5 The diffusion rate toward the cold side should be governed by 1) the slope of the a solubility line and 2) the temperature gradient, The extra complication of two-phase thermal diffusion lies in the fact that migration of hydrogen would leave the a-phase concentration gradient unaffected, since it is fixed at any temperature only by the solubility; gross concentration changes would reflect only the relative amounts of matrix and hydride, which could vary continuously at every point. Migration of hydrogen out of a region would lead to dissolution of hydride, and

Jan 1, 1962

By Thomas Fraser, David R. Mitchell

THE primary purpose of the loading plant is to transfer the finished product from the preparation machines to the railroad car, truck, or barge in which it is to go to market. Secondary purposes of the loading plant are: to prevent excessive degradation of sizes during loading, to reduce segregation as much as possible, and to prevent excessive quantities of very good or off-grade coal from entering any one car. Nonuniformity of consignments is one of the chief sources of com- plaints by consumers and coal merchants. A properly designed loading plant will do much to reduce complaints and ensure uniformity, not only from shipment to shipment but also in each individual consignment along the length of the car and in cross section. DEGRADATION IN STORAGE, LOADING AND SHIPMENT The object in loading is not only to handle the coal without breakage and segregation, but also to produce a well-trimmed load that will ride to its destination without spillage or breakage en route. The small sizes present in a car of prepared coal as received by the purchaser consist of: missed small sizes not screened out in the preparation plant, breakage during loading, and breakage caused by handling en route. For domestic sizes of anthracite shipped from the Pennsylvania anthracite field to Atlantic coast cities, the dealers&apos; loss because of break- age in loading and shipment amounts to from 2 to 5 per cent and for anthracite shipped to Middle West cities, the loss is 8 to 9 per cent. This difference is in part because dealers in the Middle West rescreen their coal more thoroughly than is usual in the East. One dealer handling Illinois No. 6 coal shipped from southern Illinois mines to Chicago reports an average size loss of 10 per cent when lump coal is unloaded with a fork. This runs as low as 5 per cent for carefully loaded coal and as high as 15 per cent for carelessly loaded coal.

Jan 1, 1943

THE papers presented by the Institute of Metals at the Detroit meeting in September, 1926, and the New York meeting, February, 1927, will be issued soon in one volume and mailed to all members of the Institute of Metals Divi-sion of this Institute. The, annual lecture given by Cecil H. Desch will begin the volume and the discussion occurring at the sessions, as well as subsequent written discussions, will be appended to each paper. The volume will contain about 600 pages, and will be sent without charge on request to any member of the Institute. The pre-subscription price to non-members is $5.

Jan 4, 1927

[MUNOZ, P.: New Oil Fields in Trinidad, M27, 311 MUNRO, C. H., biography, M84, 354 MUNROE, H. S., biography, M83, 277 Muntz metal (See also 60:40 Brass): corrosion. See Corrosion of Metals. fatigue and corrosion-fatigue, 78, 597 heat-treated: cleavage structure, 83, 498, 505 grain growth, abnormal, 83, 503, 505 machinability, 99, 323 stress-corrosion cracking, 89, 249. 266 MURAKAMI, T.: iron-silicon diagram, 80, 253, 255 MURDOCH, J. A. W., biography, M28, 157 MURDOCK, W. J.: Discussion on Adaptability of Various Coals as Generator Fuel in Manufacture of Water Gas 78, 561, 565, 566, 568 MURPHY. D. W. AND CHIPMAN, J.: Solubility of Nitrogen in Liquid Iron (T.P. 591) 116, 179. Abs., YB35, 33; M35, 114 MURPHY, L. J.: Relative Advantages and Costa of Electric Power in Lease Operations 77, 219]

Jan 1, 1936

By D. L. Luffel

This paper presents two main developments: (1) a short, constantly accelerated centrifuge method of measuring drainage capillary pressure properties of cores, and (2) a new analytic method of treatment of centrifuge measurements to obtain saturation-capillary pressure relations. Toward the first objective, a clever experimental method is presented which is certainly more rapid than previous centrifuge methods. Toward the second objective, a new analytic method is derived to eliminate the approximate method of Hassler and runner. The derivation of this new analytic method, however, appears to be in error. The new analytic solution is developed as Eq. 5 in Appendix A. At the beginning of this derivation, the average wetting phase saturation of a core is expressed as, where is the centrifuge angular velocity. Eq. D1.2 makes explicit the dependence of S and S upon The second equation shown in Appendix A expresses the relation between the three variables Since for a given porous medium the saturation is uniquely related to capillary pressure, the functional dependence of S upon P is trivial, i.e., Pc.ri does not actually appear. Thus, the function 5 (r, ) may be expressed as a new function, S*, of PC, , alone The author transforms the variable of integration in Eq. Dl through use of Eq. D2 and writes

Jan 1, 1965

By J. D. Mooney, D. L. Darnell

The accompanying chart has been drawn for the convenicncc of engineers as&apos; a means of quickly determining the correct number of plies of conveyor belts operating under specific conditions. The calculations are based on the average safe strength (factor of safety, 15) of the various standard rubber conveyor belts. The calculations assume maximum loading conditions; that is, the belt is considered as carrying the greatest load that it will handle without spillage at ordinary belt speeds. This not only produces the most economical operating conditions, but also the maximum tension in the belt. The chart is a graphical representation of the formula: Where, p = kg W(L + 10H) p = the correct number of plies k = a constant, depending on the type of drive g = the weight &apos;in pounds per cubic foot of material handled W = the width of the belt in inches L = the length of the belt in feet (approximately twice the center distance). H = the difference in elevation between the head and tail pulleys, in feet. For a simple drive, with a bare pulley, k = ----1 For a simple drive, with a rubber-lagged pulley, k = --- 1 For a, tandem drivej with bare pulleys, k = 1/375.000 For a tandem drive, with rubber-lagged pulleys, k = ---1 The chart is drawn for a simple drive, with a bare pulley (k — =e)1 ; therefore, the number of plies obtained from the chart should be multi- &apos; plied by the factor 0.83 or 5/6 for simple, lagged drive; the factor 0.67 or 2/3 for tandem, bare; and the factor 0.55 or 11/20, for tandem, lagged. The formula p = kgW(L + 10H) has been developed mathematically

Jan 1, 1916

By C. Q. Payne

(New York Meeting, February, 1912.) THE art of crushing ores and other materials by means of rolls is a comparatively recent one. While the first record of rolls using iron crushing-surfaces dates back to the year 1806, when they were employed in Cornwall, their principal development has taken place during the last 30 years. To Stephen R. Krom belongs the credit of the pioneer in introducing the belted high-speed roll, which has had its origin and a marked development in this country. His notable contribution to the art was in the use of a single bed-plate or frame supporting the roll-shafts, and to which levers holding the movable roll-bearings were pivoted. He also made use of steel tension-rods to support the crushing-strains, and of hammered-steel tires for the crushing-surfaces. These changes brought the design of crushing-rolls to a high level. Following closely thereon, about 1885, W. R. Eckart conceived the idea of the swivel or ball-and-socket support for the roll-shaft bearings. This is an excellent mechanical conception, especially for bearings held against a spring pressure, and while it may not be necessary for all types of rolls, yet it has been quite generally adopted by other roll-designers, and illustrates the refinement which roll-construction has now reached. Other engineers, as for example, Argall, Vezin, Roger, and Sturtevant, to mention only a few among many, have also given the closest attention to the various details of rolls, such as the frame, springs, bearings, and shafts, and have developed many novel and original designs. It has remained, however, for the boldness and originality of Mr. Edison to extend the field of crushing-rolls in two new directions, and to cause them to exercise new functions. In developing crushing-machinery for his Portland cement works, Mr. Edison constructed ? giant " rolls, having a diameter of 6 ft. and a length of. face of 7 ft.

Jun 1, 1912

SOUTHERN CALIFORNIA LOCAL .SECTION Executive Committee SEELEY W. MUDD, Chairman C. COLCOCK JONES, Vice-Chairman. FREDERICK J. H. MERRILL, Secretary-Treasurer, 631 Higgins Bldg., Los Angeles, Cal. RALPH ARNOLD A. B. CARPENTER The Southern California Section, held a dinner and meeting at. the Sierra; Madre Club, Los Angeles, on Friday evening, Sept. 28, 1915, at which 21 members and guests-were present. The Vice-Chairman, C. Colcock Jones; presided, in the absence of the Chairman. The amendment&apos; to the By-Laws providing for the increase of the Executive Committee from five to seven members, having been formally presented at the annual meeting of June 18, 1915, and duly announced for consideration at this meeting, was voted on and unanimously adopted. Prof. Robert H. Richards of the Massachusetts Institute of Technology; made a short address on the subject of ore concentration. The paper on the Geology and Ore Deposits of Mojave, County, Arizona, prepared by F. C. Shrader, was presented to the meeting by the Secretary and was discussed by Allen Burris and Dr. L. D. Godshall. F. J. H. MERRILL, Secretary.

Jan 11, 1915

By A. P. Woods, J. A. Elias, A. J. Heckler

A method is described by whichX-ray pole figures and axis density figures may be plotted automatically. The X-ray data are obtained using a Siemens texture gonionleter and the Schulz reflection method. Composite sampling methods are used to obtain a full quadrant of the pole figure. The contour lines of the pole figure and axis density figures are drawn using a computer-controlled x-y plotter. The computer program used to draw the contours was obtained from ZBM. POLE figures used to describe crystallographic orientations of poly crystalline sheet materials are usually plotted manually from X-ray diffraction output in the form of a strip chart recording of the intensity distribution of a given crystallographic pole in physical space. Today&apos;s computers and associated plotting equipment now make it possible to plot pole figures and axis density figures automatically. Inverse pole figures have been determined by mathematically "inverting" X-ray pole figure data.&apos;-&apos; In general, these methods require complicated, time-consuming numerical calculations. A more economical but less accurate method is to determine the axis densities of low-index crystallographic poles using an X-ray diffractometer. When these axis densities are plotted in a unit stereographic triangle contour lines can be drawn to represent the axis density distribution. This can now be done automatically. Computers were used to plot pole figures by a method developed by Holland, Engler, and powers.&apos; In their method intensity ratios based on a random standard sample were obtained from a strip chart recording, and the stereographic (x, y) coordinates of these ratios were determined by a computer. Symbols characteristic of different intensity ratio levels were then plotted using an automatic x, y plotter and intensity contours were drawn manually. The present paper describes a method by which pole figures and axis density figures have been automatically plotted from digital data obtained from a Siemens X-ray unit. Plotting was accomplished using an IBM 1620 computer and a Calcomp 563 digital plotter. COMPUTER PROGRAM The computer program was obtained from IBM Systems Reference Library, No. 1620-CS-05X, and was designed to plot contour maps from randomly distributed data. It consists of a set of twelve separate subprograms, four of which were used in this work. The program takes a given distribution of data points and by a numerical method determines the values at mesh points of a square grid system superimposed over the input data. The output data from this program is in a form suitable for input to the contour plotting program. A smoothing program is also available which calculates new mesh point values from a continuous function fitted to neighboring mesh points. The degree of smoothing depends on the number of points around a given grid point which are used to adjust or smooth the grid value. The contour plotting program is designed to allow the user to specify the interval, scale, and annotation of the contours to be plotted. EXPERIMENTAL PROCEDURE Pole Figure Data Points. Diffracted X-ray intensities were determined using a Siemens texture goniometer and the schulzs reflection method. Due to geometric

Jan 1, 1968

By J. C. Mertz

ACCURATE knowledge of the solid solubilities of the elements that dissolve in the important base metals is needed for guidance in the preparation and heat-treatment of the alloys derived from these compo-nents. While there is still difference of opinion concerning the merits of the X-ray and microscopic methods of determining such solubilities, it is certainly true that the recent extensive use of X-ray diffraction to review the existing constitutional data has revealed many glaring inaccu-racies and has brought about a much improved knowledge of phase-boundary locations, which will inevitably come to include all of the important alloy systems. When the work is done with all necessary precautions it appears that in the majority of cases where the solubilities extend beyond a few tenths of a per cent the X-ray back-reflection technique is capable of furnishing the best of information in this field. For the most prolonged and thorough studies it is obviously advisable to combine the results of several methods, in particular, to obtain an agreement between X-ray and microscopic data. This paper reviews the work previously done on the solubilities of phosphorus, arsenic, antimony and bismuth in copper and, in considera-tion of the uncertainties thus made apparent, presents, new X-ray data obtained with the first three members of this group.

Jan 1, 1936

(Members are urged to send in for this. column any notes of interest concerning themselves or their fellow-members.) Members and guests who called at the Institute headquarters during the period Sept. 10, 1916 to Oct. 10, 1916. Arthur K. Adams, Chanaral, Chile. C. F. Moore, Salt Lake City, Utah. Hiram W. Belnap, Washington, D. C. L. D. Moore, Providence, R. I. E. A. Bridgman, Seattle, Wash. George A. Morrison, Chicago, Ill. D. W. Buckly, Wallace, Idaho. Pablo Ortega, Havana, Cuba. G. L. Carlisle, Jr., New York, N. Y. L. W. Paige, New York, N. Y. Ernest H. A. Cohen, Johannesburg, So. Africa. Charles Petzel, New York N. Y. A. Faison Dixon, Camp Rio de Oro, Venezuela. C. A. Pierce, Patagonia, Arizona. Charles E. Dutton, Goldfield, Nev. W. E. Pomeroy, El Paso, Texas. D.-F. Hewitt, Washington, D. C. George S. Rice, Washington, D. C. . James E. Howard, Washington, D. C. G. J. Schofield, Seattle, Wash. A. 0. Ihlseng, Joplin, Mo. Warren D. Thompson, New York, N. Y. I. Ishikawa, Niagara Falls, N. Y. M. M. Valerius, Tulsa; Okla. Montrose L. Lee, New York, N. Y. G. B. Waterhouse, Buffalo, N. Y. V. H. McNutt, Billings, Mont. Joel H. Watkins Washington, D. C. Benjamin L. Miller, So. Bethlehem, Pa. H. P. Wherry, Chicago, Ill. Arthur K. Adams has left for Chile, where he will act as geologist for the Andes Copper Co., a subsidiary of the Anaconda copper company.

Jan 10, 1916

By R. C. Wilcox, R. V. Lawrence, P. A. Calhoun

The V-Rh-Si, Nb-Rh-Si, and Cr-Rh-Si systems were investigated to evaluate the extent of solid solubility between binary Cr3O structures. All Cr3O components lie within the favorable atomic size range1 for the formation of the Cr3O structure. Previous studies indicated complete solid solubility between V3Si and V3Sn2 and no solubility between Sn and cr3si3 or Si and Nb3Rh.4 The Cr3O structure is not found in the Cr-Sn and Nb-Si binary systems. Powder compacts were are-melted under argon, homogenized in a vacuum at 1000°C, and water-quenched. Alloys containing greater than 15 at. pet Si were annealed 100 hr. X-ray diffractometer methods were used to study all systems utilizing copper radiation for the Cr-Rh-Si system and chromium radiation for the other two systems. V-Rh-Si System. The alloys prepared in the V-Rh-Si system and the measured lattice parameters for the Cr3O structure found in each alloy are listed in Table I. The characteristic Cr3O diffraction pattern was found in all binary alloys. The measured lattice parameter of V3Rh (VRS-1) is in agreement with the reported value5 while the value for V3Si (VRS-5) is only in fair agreement.&apos; In

Jan 1, 1965

By G. Purcell, S. C. Sun

In an attempt to determine the relative collecting ability of 18-carbon fatty acids, studies were performed on rutile in aqueous solutions of the fatty acid soaps. The preceding article reported the electro-kinetic properties; this article outlines the flotation behavior. Results of these flotation experiments are described and correlated with the electrokinetic results. Recent studies of the electrokinetic1-4 and the electrochemical5,6 properties of a few solid-liquid interfaces have provided a better understanding of the flotation process. A number of investigators have attempted to determine the relative collecting ability of 18-carbon fatty acids, but their published results (even for the same mineral) vary widely. Such lack of agreement indicated a need for further investigation. In an effort, therefore, to resolve the problem, electro-kinetic studies were made on rutile in aqueous solutions of the fatty acid soaps. Following the determination of the electrokinetic properties, the flotation behavior of rutile was studied. Results of these flotation experiments are described in this paper and are correlated with the electrokinetic results. MATERIALS AND EXPERIMENTAL PROCEDURE Materials: Pure -28, + 35-mesh rutile crystals were used for all flotation tests, and nitrogen-saturated conductivity water was used throughout. Sodium hydroxide and hydrochloric acid were added for pH regulation. The methods of purification for these materials and the preparation of the soaps have been described elsewhere. 7 Equipment: A Hallimond cell, constructed in a manner similar to that described by Fuerstenau, Metzger and Seele,8 was used for the flotation of mineral particles; however, a coarse pyrex frit was substituted for the capillary. Procedure: Purified nitrogen was led through a two- way stopcock into a graduated cylinder partly filled with water. The gas forced water from the cylinder back into a header tank until the water level in the cylinder coincided with a predetermined mark. Reversal of the stopcock then allowed water in the tank to force nitrogen into the cell until the water in the graduated cylinder rose to a second predetermined mark. In this way a constant volume of nitrogen under practically constant pressure was used for each flotation test. However, the flotation time varied, depending upon the amount of mineral floated and the pH of the solution. Rutile crystals were transferred under water from a storage bottle by a glass scoop holding 1.7 g. Consistency of the scoop samples was good, varying from a low value of 1.67 to a high of 1.74 g. The water added to the conditioning bottle during mineral transfer was drained off, and then 2 cu cm of either hydrochloric acid or sodium hydroxide were added. The concentration of pH regulator was adjusted to give approximately the final soap solution pH that was required. The order of addition of reagents did not affect the results within the limits of experimental error. Soap solution of the required concentration was added under nitrogen pressure to fill the bottles completely. Conditioning for 1 hr was carried out on rolls rotating at 35 rpm. After conditioning, 2.5 cu cm of solution were run off into the container of a Beckman (model G) glass electrode pH meter. The electrodes were rinsed in this solution, which was then discarded, and 2.5 cu cm more were added for pH determination. The remaining solution and the mineral were transferred to the cell; care was taken to ensure that all mineral was washed out of the bottle by the conditioning solution. With the cell back in its flotation position the liquid just reached the desired level, and the test was started immediately. The amount of agitation in the cell was kept constant, and flotation was carried out without the use of a frother. In each series of ten tests one was run with no collector added to ensure that the mineral had not become contaminated, and two were conditioned at the same pH to check reproducibility. After each test the cell was dismounted, soaked in cleaning solution, washed in hot water and then rinsed with distilled water.

Jan 1, 1963

By I. Cornet

INTRODUCTION WITH the greatly expanding use of magnesium during the war, it appeared necessary to the War Metallurgy Committee that the notch sensitivity of magnesium alloy extrusions be further investigated and the influence of various factors upon notch sensitivity be noted. Accordingly, the National Defense Research Committee of the Office of Scientific Research and Development placed a research contract with the University of California, supervised by the War Metallurgy Committee. The work discussed herein was done under "Restricted" Project NRC-21, reported in Dec. 1943 1; it has been released for publication by the O.S.R.D. SCOPE OF THE INVESTIGATION The notch sensitivity of various magnesium alloy extrusions was determined under axial tension, and also under several conditions of nonaxial tension. Hardness, grain size and other metallographic features were observed; stress-strain data were obtained, and the chemical compositions of the alloys were determined, in order to correlate these quantities with the notch sensitivity. Notch sensitivity under axial tensile load was determined for a few specimens which had been cold worked to various degrees by tensile prestraining. Magnesium alloy extrusions studied included Dowmetal 0, X, J, and M. For comparison, extrusions of aluminum alloy 24S-T, cast bars of aluminum alloy I22-T2, and cast bars of magnesium alloy C were also tested, The specified chemical composition of these alloys is given in Table I. All bars tested were within specification limits of composition. Investigation of the tensile notch sensitivity of various magnesium alloy extrusions, under conditions of axial and eccentric load, showed little or no correlation with stress-strain or other conventional data. Since the many uncontrolled variables present might mask significant relationships, one alloy was selected for intensive study. Magnesium 0 alloy extrusions were subjected to experimental heat treatments, and the changing hardness, tensile strength, microstructure, and notch sensitivity observed. EXPERIMENTAL TECHNIQUES AND PROCEDURES Tensile Testing Bars used for axial loading were machined with 3/8 in.- and with 1/4-in. minimum diam, and included specimens with 6o° V notches (Fig I and 2). Each V-notched specimen was roughed out carefully and then finished with a honed tool. These V-notched bars were sampled frequently, sectioned, polished, and examined at 500 X magnification to control

Jan 1, 1948

By I. Cornet

With the greatly expanding use of magnesium during the war, it appeared necessary to the War Metallurgy Committee that the notch sensitivity of magnesium alloy extrusions be further investigated and the influence of various factors upon notch sensitivity be noted. Accordingly, the National Defense Research Committee of the Office of Scientific Research and Development placed a research contract with the University of California, supervised by the War Metallurgy Committee. The work discussed herein was done under "Restricted" Project NRC-21, reported in Dec. 1943~; it has been released for publica-tion by the O.S.R.D. Scope of the Investigation The notch sensitivity of various magnesium alloy extrusions was determined under axial tension, and also under several conditions of nonaxial tension. Hardness, grain size and other metallographic features were observed; stress-strain data were obtained, and the chemical compositions of the alloys were determined, in order to correlate these quantities with thc notch sensitivity. Notch sensitivity under axial tensile load was determined for a few specimens which had been cold worked to various degrees by tensile prestraining. Magnesium alloy extrusions studied included Dowmetal 0, X, J, and A(. For comparison, extrusions of aluminum alloy 24s-T, cast bars of aluminum alloy 122-T2, and cast bars of magnesium alloy C were also tested. The specified chemical composition of these alloys is given in Table I. All bars tested were within specification limits of composition. Investigation of thc tensile notch sensitivity of various magnesium alloy extrusions, under conditions of axial and eccentric load, showed little or no correlation with stress-strain or other conventional data. Since the many uncontrolled variables present might mask significant relationships, one alloy was selected for intensive study. Magnesium 0 alloy extrusions were subjected to experimental heat treatments, and the ,Changing hardness, tensile strength, microstructure, and notch sensitivity observed. Experimental Techniques and Procedures Tensile Testing Bars used for axial loading were machined with % in.- and with 34-in. minimum diam1 and included specimens with 60" V notches (Fig I and 2). Each V-notched specimen was roughed out carefully and then finished with a honed tool. These Y-notched bars were sampled frequently, sectioned, polished, and examined at 500 X magnification to control

Jan 1, 1949

(The following list contains the names of those members of the Institute of whose connection with military service we have only recently become acquainted; it also includes the names of a few who have recently been promoted or transferred, indicated by a *. A complete list was published in the Year Book, issued as a supplement of the Bulletin for March, 1918.) *AMBLER, HARRY A., 1st Lieutenant, 0. R. C., 30th Infantry, A. E. F. BAKER, R. F., Private, Intelligence Section, Headquarters 90th Division. *BARTON, L. A., Captain, 604th Engineers. *BATTEN, H. L., Lieutenant, Canadian Engineers, C. E. F. *BENSEL, J. A., Major, U. S. Reserves. BIRKETT, HOWARD, Lieutenant, Aviation, U. S. Signal Corps. BLOOMFIELD, E. C., Lieutenant, 1st Canadian Tunnelling Co. BOOTH, L. E., Watertown Arsenal, Det. E. 0. C., N. A., Watertown, Mass. *BOWMAN, REGINALD G., 1st Lieutenant, Engineers, U. S. R., Int. Ord. Dept. No. 4, A. E. F. *BRADLEY, CLARENCE I., Convois Automobile Section 585,. S. S. U., P. A. R., B. C. M.

Jan 7, 1918

COMMITTEE IN CHARGE SPENCER PENROSE, Chairman A. E. CARLTON, Chairman Finance Committee GEORGE M. -TAYLOR, Vice-chairman. J. DAMSON HAWKINS, Secretary DENVER COLORADO SPRINGS Finance Finance T. B. STEARNS A. E. CARLTON RICHARD A. PARKER SPENCER PENROSE T. B. BURBRIDGE GEORGE M. TAYLOR A. L. BLOOMFIELD, Treasurer Arrangement Registration DAVE G. MILLER LOREN C. LENNOX FRANK BULKLEY HORACE F. LUNT GEO. E. COLLINS J. M. TIPPETT Entertainment Arrangement and Entertainment F. H. BOSTWICK GEORGE M. TAYLOR F. E. SHEPARD J. D. HAWKINS HOWLAND BANCROFT A. E. CARLTON B. P. MORSE A. L. BLOOMFIELD J. G. PERRY THOMAS B. CRONE E. P. ARTHUR ETIENNE A. RITTER CRIPPLE CREEK PUEBLO THOMAS B. CRONE J. F. WELBORN E. B. ARTHUR H. B. CARPENTER N. S. GREENSFELDER L. B. EAMES A. E. CARLTON F. ROBINSON B. F. HILL J. G. WILLIS

Jan 8, 1918

New York Meets first Wednesday after first Tuesday of each month. Chairman. PERCY E. BARBOUR, Vice-Chairman. A. D. BEERS, Secretary, 55 Wall St., New York, N. Y. C. A. BOHN, Treasurer. JOHN V. N. DORR, LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. R. L. AGASSIZ, Chairman. JAMES G. CARLETON, Vice-Chairman. E. E. BUGBEE, Secretary-Treasurer, Mass. Inst. of Technology. Cambridge, Mass. W. E. C. EUSTIS, G. A. PACKARD. Columbia Holds four sessions during year. Annual meeting in September or October. W. H. LINNEY, Chairman. OSCAR LACHMUND, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. STANLY A. EASTON, S. SHEDD. Puget Sound Meets second Saturday of each month SIMON H. ASH, Chairman. I. F. LAUCKS, Vice-Chairman. CHARLES SIMENSTAD, Secretary-Treasurer, 425 Lyon Bldg., Seattle, Wash. GLENVILLE A. COLLINS, JOHN N. POTT

Jan 6, 1917

By Ronald C. Koo

THE effect of grain size on the mechanical properties of the bcc metals has been a subject of intensive theoretical and experimental study.&apos;-l5 Quantitative relationships have been established experimentally between yield stress and grain size and between the ductile-brittle transition temperature and grain size in a number of metals.6"15 Much significance has therefore been attached theoretically to the grain size dependence. In all these experiments, different grain sizes were always achieved by annealing specimens at various temperatures. The implicit assumption was that any change in the dislocation substructure or in the distribution of impurities which might occur simultaneously with the production of various grain sizes had only a negligible effect on the mechanical properties. The validity of this assumption, however, is questionable. transformation in iron-nickel alloys is actually an extraneous phenomenon due to inadvertent compositional changes in the martensite if the heating rate is not sufficiently rapid. This complication can be avoided by up-quenching for the reversal treatment,5 and then the stabilization does not appear. Clearly, the lattice imperfections and strengthening produced by the reverse transformation are not responsible for the marked stabilization which has been observed by other investigators in these alloys. Data will be presented in this note to show that, at least in recrystallized tungsten of commercial purity, the difference in the ductile-brittle transition temperature of specimens annealed at various temperatures is more a result of a variation in the distribution of impurities rather than of the difference in grain size produced by the anneal. Ductile-brittle transition temperatures in tension were determined on powder-metallurgy tungsten specimens recrystallized at various temperatures. Tensile specimens having a gage length of 1.50 in. and gage diam of 0.18 in. were recrystallized at 1450°, 2000°, 2350°, 2550°, 2750°, or 2800" for 30 min in a vacuum furnace at a pressure of 1 x 10"5 mm of Hg and then tested at a constant extension rate of 8 x 10 per sec in an argon atmosphere from 100" to 800". Typical quantitative analyses of impurities are given in the Table. These results show that, within the precision of the analyses, see Table, annealing did not result in any detectable change in the impurity contents of the specimens, nor was there any detectable difference in purity between specimens having large differences in grain size annealed at the same temperatures . The results of the tensile tests yielded three distinct ductile-brittle transition curves approximately 225&apos; apart. As shown in Fig. 1, data of specimens annealed at 1450°C and those of specimens annealed at 2000°C (O) fell on Curve A. Data of specimens annealed at 2350" and 2550°C fell on Curve B, and those of specimens annealed at 2750" and 2800°C fell on Curve C. The decrease in ductility with increase in annealing temperature became so pronounced that one third of the specimens annealed at 2750" and two thirds of the specimens

Jan 1, 1963

By P. R. Celmer, Leonard R. Weisberg

THE principle of fractional crystallization has been successfully used to prepare high-purity (99.999 pct) Ga. Hoffman and Scribnerl removed single crystals of gallium solidifying in a gallium melt, while Zimmerman2 grew single crystals from the melt by the Kyropolous technique. In contrast, attempts at purifying gallium by zone refining have been less successful. ichards, reported that despite the passage of 40 zones through a gallium ingot, there still remained 5 to 70 ppm each of Cu, Fe, Ca, Mg, Si, Al, and Ag. Previously, Detwiler and Fox4 detected only one impurity, Pb, segregating in zone-refined ingots. These surprising results prompted an investigation of the factors controlling impurity segregation in gallium. Possible reasons for this were insufficient diffusion of impurities in the melt; recontamination of the melt by its oxide film which is not affected by the passage of the zone; reaction of gallium with the boat; sudden freezing of gallium following supercooling, especially since gallium easily supercools to and trapping of impurities at grain boundaries. Impurity segregation tests were carried out by directionally freezing gallium using the Bridgman rnethd, modified in that the molten gallium is lowered out of a furnace into a slush of dry ice and trichloroethylene, thus minimizing supercooling. Since the gallium is contained vertically, the oxide film is in contact only with the tail end of the melt. It was found that Teflon makes an excellent crucible for gallium since it is quite pure, non-reactive, translucent, flexible, machinable, and is not wet by gallium. The gallium crystals could be grown at various speeds, and the melt could be vigorously stirred by a Teflon rod moving through the gallium in a vertical reciprocating fashion. Single crystals could be grown by placing a solid Teflon plug at the bottom of the melt drilled out in such a way to cause the solidifying gallium to follow a winding path. Thus, even if many crystals are originally nucleated, only one grain will predominate. The grain structure of the gallium crystals was revealed by an etchant composed of equal volumes of HC1, HNO3 and HF, diluted with water to half strength. Emission spectrographic analyses were carried out on samples removed from the front and tail ends of the resulting gallium ingots. Typical results of this study are summarized in Table I. The rate of freezing in all three cases was about 1 in. per hr. It can be seen that even though stirring of the melt does help, it is even more important to grow a single crystal of Ga in order to obtain good segregation of impurities. The effect of crys-tallinity on the segregation of impurities was previously observed6 in the directional freezing of germanium; however, in this case, the effect was much less pronounced. This dependence of impurity segregation on the crystalline perfection of Ga may be related to its thermal conductivity which is the most anisotropic of all metals.7 The anisotropic thermal conductivity can cause the solid-liquid interface to be nonuniform, thus leading to trapping of impurities during freeing, and therefore reduced segregation. In conclusion, it is indicated that zone refining of gallium would be more successful if seeding and similar precautions are taken to insure single crystal growth. The authors are indebted to Mr. H. H. Whitaker for the spectrographic analyses and to Drs. B. Abeles and F. D. Rosi for helpful advice and encouragement throughout the course of this work. This research was supported by the Electronics Research Directorate, Air Research and Development Command, under Contract No. AF33(616)-5029. REFERENCES &apos;J. 1. IToffmon and B. T. Scribrer: I. Research h&apos;atl. Bur. Standards, 1935, "01. 15, p. 205. &apos;W. Zirnmerman: Science, 1954, vol. 119, p. 41. %J. L. Richards: Nature, 1956, vol. 117, p. 182. &apos;D. P. Detwiler and W. M. Fox: I. Metals, 1955, "01. 7, p. 205. 5P. W. Bridgman, Proc. Am. ilcod. Sci., 1925, vul. 60, pp. 305,385,423. "S. L1. Christian: private c ommuni cation. &apos;K. W. Powell: roy. Sac., 1951, vol. 209, p. 525. &apos;W. G. Pfann: Zone Re fining, p. 20. John Wiley and Sons, Inc., New York, L058.

Jan 1, 1962