Societies and Academies

Abstract

LONDON. Institute of Metals, Sept. 15 (Annual Autumn Meeting, Zurich).—A. J. Murphy: The constitution of the alloys of silver and mercury; with an appendix by G. D. Preston on the X-ray examination of the system silver-mercury. Progressive additions of mercury to silver cause a continual reduction in the temperature of the initial freezing point down to -38.8° C., the freezing point of mercury. No alloy in the series has a freezing point lower than that of pure mercury. Silver can retain in solid solution 55 per cent by weight of mercury at 276° C., the amount probably increasing somewhat at lower temperatures.—A. von Zeerleder: Influence of variations in heat-treatment and ageing on duralumin. Quenching in hot water or in oil causes less deformation, and if the temperature of the quenching medium, as well as the ageing temperature, be 50°C, there is no disadvantageous influence on the physical properties. Measurements of the electrochemical potential, electrical conductivity, tensile and corrosion properties showed that a temperature of 145° C. (293 ° F.) had a decidedly disadvantageous influence.—W. E. Alkins and W. Cartwright: Experiments in wiredrawing. (1) Behaviour of a composite rod. Composite round rods of annealed copper, built up by drawing a number of tubular layers of equal thickness over a central solid core, have been drawn in drafts of varying severity through straight-sided dies of three different angles of taper. Butt ends when drawn through the dies become concave without showing any steps between the layers; the concavity increases with the angle of taper of the die and also with the amount of reduction at the draft. All the layers undergo a proportionate reduction in thickness and therefore the same relative reduction in area of cross-section.—E. L. Francis and F. C. Thompson: The drawing of non-ferrous wires. The power required to draw wire is directly proportional to the maximum stress of the original material. With tungsten carbide dies, the pull required is practically independent of the speed of drawing over a wide range. A comparison is made between the efficiency of steel, carbide, and diamond dies.—H. W. Brownsdon and E. H. S. van Someren: Application of the spectrograph to the analysis of non-ferrous metals and alloys. The possibilities and limitations of spectrographic methods are reviewed. Methods for the routine spectrographic examination of brass and some lead alloys are outlined, and tables are given indicating the relationship between impurity or minor constituent concentration and relative line intensities.—D. M. Smith: The spectrographic assay of some alloys of lead. The method is based on standards of known composition either synthetically prepared or determined by accurate chemical analysis. One of its great practical advantages is that it is very much more rapid than ordinary chemical assay of these metals. Spark spectra are preferred, as giving more consistent results than arc spectra. By simple direct comparison of spectra the constituents can be determined within the range 0.1–1 per cent, with an accuracy of 10 per cent. —John L. Haughton and Ronald J. M.Payne: Transformations in the gold-copper alloys, with an appendix on X-ray examination of gold-copper alloys, by G. D. Preston. By recording autographically the variation of resistance with changing temperature of alloys of composition ranging between 20 per cent and 70 per cent atomic of gold, and by measurements of the specific resistance of alloys slowly cooled to room temperature, the transformations in alloys with compositions in the neighbourhood of those corresponding with the compounds AuCu and AuCu3 have been confirmed, and the presence of another transformation in alloys approximating to the concentration of compound Au2Cu3 has been established.—N. S. Kurnakow and N. W. Ageew: Physico-chemical study of the gold-copper solid solutions. Both annealed and quenched alloys were studied. The existence of the compounds AuCu and AuCu3 has been confirmed by constructing isothermal diagrams of the electrical resistance, and the limits of the solid solutions have been indicated.—M. Cook and E. C. Larke: Physical testing of copper and copper-rich alloys in the form of thin strip. Consistent results for tensile strength and elongation are obtainable on all the materials down to and including 0.02 in. thickness. One of the most satisfying methods of measuring hardness is the diamond pyramid static indentation method. Cupping machines, although they may measure some kind of ductility and, if properly correlated, may afford a good sound indication of the behaviour of a material for cupping and drawing operations, are limited in respect of specification.