An Investigation of the Alloy System of Aluminium, Copper, and Zinc

In conclusion, the present .experiments are summarized as follows: (I) L5 alloy was quenched at various temperatures, and the phenomena of ageing were observed. The influence of quenching was marked in the alloy quenched at higher temperature, and hardening was found to be marked in the alloy containing less amount of copper. Also hardening was found to take place in two steps. (2) The effect of tempering at 150°-200° C. was observed to result in softening of the alloys, but hardness and tensile strength were somewhat improved by tempering at 200°-300° C. The effect of tempering was marked in the alloy containing 3 per cent of copper than that of less content of copper. (3) Quenching was carried out of 4 series of alloys whose content of copper varied from o 7 to 4.6 per cent , and whose content of zinc varied from 4 to 20 per cent. A complicated relation was found to exist between age-hardening and composition of alloys. (4) Thermal expansion of quenched specimens were measured, and the irregular change of expansion was found not to be the direct indication of hardening due to tempering or ageing. (5) Age-hardening was considered to be due to the spontaneous crystallization of solute phase or phases in a super-cooled solid solution. As the mechanism of hardening it was also considered that the separation of the second phase or phases accompanying with the disintegration of solvent lattices gave rise to hardening on one side, and on the other, internal strain produced in crystals, owing to the rapid change of lattice construction

On the Age-hardening of Aluminium-rich Al-Zn alloys

(1) The phenomena of age-hardening were observed on the Al-rich Al-Zn alloys, when the zinc content exceeded 5%, and these alloys were divided into 2 kinds at 26% zinc, according to their properties. (2) Al-Zn series showed an eutectoid transformation at 256°C, and this transformation was observed on the alloys containing more than 20% zinc. The solubility of zinc in aluminium was found to be less than 5% at 110°C. Owing to these facts, the equilibrium diagram on the aluminium side was obtained. (3) It was found that age-hardening did not always concern a compound. The question is the solubility of a solid solution. (4) Age-hardening was considered to be due to the spontaneous crystallisation of a super-cooled solid solution. With this conception, the phenomena of hardening were explained. (5) As the mechanism of hardening it was found that the separaticn of a second phase in finely divided perticles gave rise to hardening on the one side, and on the other the disintegration of the grains

Investigation of Al-Zn-Mg Alloys on the Zn-Al Side

The constitutions of the alloys of aluminium, zinc and MgZn₂ were investigated, and the equilibriums on the side of zinc and aluminium were determined. From these experimental results, we obtained a general diagram as shown in Fig.11. Table 3 shows the solidification and transformation process of this system considered from this diagram

Effect of Strain Rate on the Piastic Deformation in Aluminium Single Crystals

This paper was read on April 2nd, 1950 at the Spring Meeting of the Institute of Metals of Japan.A survey of the fine structures of slip bands in the electrolytically polished aluminium single crystals which were subjected to the extension of various loading rates was made by electron-microscope and X-ray. The results obtained were as follows; (1) The specimen subjected to a slow rate of strain generally shows the wider slip bands, the wider spacings between slip bands and the larger number of sets of the active gliding planes than the specimen subjected to a rapid strain rate. (2) The slowly deformed specimen generally gives rise to pronounced X-ray asterism and remarkable plastic flow in the surface layer than the rapidly deformed specimen. (3) Submicroscopic slips take place within the regions between the obvious slip bands. (4) The slopes of the surface of the test specimen produced during plastic deformation were determined by the stereographic analyses of the electron-micrographs. (5) Effect of the notch line of the surface on the behavior of the slip bands was observed