抄録
The ageing characteristics of the Cu–Be–Al ternary alloys, containing 9∼11 at% Be and 6∼9 at% Al, were studied by means of hardness and tensile tests, optical and transmission electron microscopy, X-ray and electron diffraction, and calorimetric measurements. The investigation was done mainly on the specimen containing 9.07 at% Be and 9.05 at% Al, which was initially quenched from 800°C, where the two phases (α and β) are in equilibrium, and then aged at 340°C for various periods. The changes in various properties during ageing were due to the precipitation in the α phase and the decomposition of the β phase, both of which terminated in the equilibrium state, (α+γ). The most hardened state attained by 1.5 hr ageing was attributed to the formation of G.P. zones in the α phase and the decomposition of the β phase into the α and intermediate phases. The crystallographic orientation relations between the matrix and these phases in the course of the ageing process were determined. Finally the age-hardening of the alloys was briefly discussed.
