Acceleration of α Precipitation and Strengthening of Ti-15V-3Cr-3Sn-3Al Alloy by Two Step Aging

Abstract

Acceleration of α precipitation and strengthening of metastable β titanium alloy, Ti-15V-3Cr-3Sn-3Al (15-3), by 2 step aging was investigated.
Ti-15V-3Cr-3Sn-3Al alloy shows a phase-separation of β phase in low temperature aging at 573K after β solution treatment. Precipitation of small particles of α phase in the second stage high temperature aging was accelerated by phase separation in which β' phase precipitates, because β' precipitates provided the nucleation sites of α precipitates.
Higher strength by shorter total aging time could be attained by 2 step aging in the combination of 1st step aging of 573K, (14.428.8)ks aging and 2nd step aging of (753813)K, (3.686.4)ks aging.