Abstract
GLASGOW. Institute of Metals, September 21.—Donald Ewen and Prof. T. Turner: The shrinkage of antimony-lead alloys and of the aluminium-zinc alloys during and after solidification. From the investigation of the shrinkage of the brasses it has been suggested that, for an alloy of given composition, a direct proportion exists between the amount of expansion on solidification and the distance of the solidus from the liquidus at this composition on the equilibrium diagram. The results of shrinkage tests on two further series of alloys are included in this paper; they show that the above theory is incapable of general application, and appear to indicate that it obtains only in the case of alloys containing solid solutions.—F. Johnson: The effect of silver, bismuth, and aluminium on the mechanical properties of “tough-pitch” copper containing arsenic. Contrary to the general belief, it was found that bismuth increased the tensile strength, as did silver also. It was found that silver had little effect upon the toughness of the arsenical copper, which, again by virtue of the presence of arsenic, was tougher than electrolytic copper made under similar conditions. The effect of silver on the hot-working properties was found to be negligible up to 0.3 per cent.; that of bismuth noticeable above 0.02, and serious above 0.05 per cent.; whilst that of aluminium was ruinous at 0.3 per cent. In view of the possibility of modern commercial copper containing other impurities which could modify the limiting proportion allowable of the above-mentioned impurities, it is difficult to fix a limit beyond which they should not occur. It may, however, be safely said that silver occurs in such traces that its presence may be ignored. Its influence will be beneficial rather than harmful. Bismuth should, preferably, be entirely absent, and may be expected to cause trouble in any process of mechanical treatment at a red-heat, if present above 0.01 per cent. As regards the presence of this impurity in the finished material, however, little concern may be felt, as the amount which will render arsenical copper unfit for working hot, will have ho serious effects on the mechanical properties of the finished material in the cold.—A. D. Ross: Magnetic alloys formed from non-magnetic materials. The paper deals with investiga-tions carried out chiefly on ternary alloys consisting of copper, manganese, and one of the elements aluminium, tin, bismuth, and antimony. All the groups show fair magnetic quality, but the most interesting are the ternary alloys containing respectively aluminium and tin. Some of the former are, under small magnetising forces, much more magnetic than cobalt, and have little coercive force. The tin alloys are less permeable, but exhibit greater hysteresis. Most of the alloys have their magnetic quality improved if they are annealed for a short time at a moderate temperature, 150°-200° C. Prolonged annealing has invariably an adverse effect, the hysteresis loss increasing rapidly with time. The behaviour of the alloys on cooling to the temperature of liquid air is peculiar and characteristic. For low and moderate fields the process results in general in a decided increase in susceptibility, whereas almost all other magnetic materials are rendered less susceptible.
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Societies and Academies . Nature 84, 421–422 (1910). https://doi.org/10.1038/084421a0
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DOI: https://doi.org/10.1038/084421a0