Societies and Academies

Abstract

LONDON Institute of Metals (Silver Jubilee Autumn Meeting at Birmingham), September 18-21. N. AGEEW and D. SHOYKET: Constitution of the silver-rich aluminium-silver alloys. The constitutional diagram has been determined by micrographic examination, X-ray analysis, and hardness measurements. The αβ-phase (Ag3Al) is converted on heating above 400° C. into a mixture of α and β. The α- and β-phase boundaries at high temperature have been determined by precision measurements of the lattice parameter and by micrographic examination of the quenched alloys. The α-phase is stable only at high temperatures, and below 600° C. is converted into the α + β eutectoid. W. E. ALKINS and W. CARTWRIGHT: Experiments in wire-drawing. (3) Annealing of H.C. copper wires drawn to varying degrees of hardness. The annealing behaviour depends not so much on the original tensile strength of the wire as on the amount of reduction by cold-work which it has undergone. The more lightly drawn wires show an appreciable increase in strength after annealing at low temperatures. They retain their strength at temperatures up to, say, 250° C, very much better than the harder wires α the latter begin to soften at temperatures little above 100° C, and the rate at which strength is lost increases with increasing cold-work. After all heat-treatments of sufficient severity to effect more or less ‘complete’ annealing, the breaking load is lower the less the amount of cold-work done on the wire, and it increases steadily with increasing cold-drawing until the three most severely drawn wires of all are reached, when there are fairly definite indications of a decrease in the strength of the fully annealed wire. N. P. ALLEN: Distribution of porosity in aluminium and copper ingots, with some notes on inverse segregation. In three copper ingots and four aluminium alloy ingots cast in a specially tapered mould, the distribution of porosity followed the probable form of the isotherms in the cooling mass, and was much influenced by the mould taper. The type of micro-structure also had an influence on the distribution of porosity. The inverse segregation of two aluminium-copper alloy ingots was closely related to their porosity. G. D BENGOUGH and L. WHITBY: Magnesium alloy protection by selenium and other coating processes (2). Small losses of weight of Elektron alloy AZM (sheet) resulting from corrosion by immersion in, or spraying with, sea-water are associated with serious losses of elongation. Visual inspection did not suggest the extent of the damage, which occurred even when the alloy was protected by chemical coatings and paint. H. W. BROWNSDON, MAURICE COOK and H. J. MILLER: Properties of some temper-hardening copper alloys containing additions of nickel and aluminium. When nickel and aluminium are present in certain quantities and ratios, the alloys are softened by quenching from relatively high temperatures, and the quenched alloys, both in the soft and cold-worked conditions, harden considerably when reheated or tempered to an intermediate temperature somewhat below the annealing temperature. H. J. GOUGH and D. G. SOPWITH: Corrosion-fatigue characteristics of an aluminium specimen consisting of two crystals. The specimen was tested under alternating torsional stresses in a slow stream of tap water. The intercrystalline boundary was not attacked by the corrosive medium, nor did it influence in any visible manner the method of failure of the specimen, which took place primarily by the formation of cracks in areas undergoing heavy plastic deformation. On the surface of the specimen these cracks were generally parallel to the traces of the operative slip-planes—in several cases they had their origin at holes situated in the most highly stressed regions of the origin of these holes no definite evidence is available. (To be continued.)