Microstructure, texture and mechanical properties of metastable beta titanium alloy Ti-5Al-5Mo-5V-3Cr

Abstract

ABSTRACT Present work describes the evolution of microstructure, texture and mechanical properties of the alloy Ti-5Al-5Mo-5 V-3Cr as a function of ageing temperatures and time intervals. The hot-rolled sheet of the pancake was solution treated in β phase field and water quenched (β ST WQ) and aged. The β ST WQ sample of the alloy exhibits single β phase. The β ST WQ samples were initially aged at 300°C for 30, 60 and 90 min and again aged at 550 and 750°C for different ageing times. The ageing has resulted in different morphologies of the α phase precipitates. These are grain boundary α, sub boundary α, islands α and uniform distribution of α within prior β grains. The sizes and volume fractions of the α phase increase and decrease with increase in ageing temperature, respectively. The higher ageing temperature (750°C) results in precipitation-free zone within the vicinity of prior β grain boundaries. . The basal texture observed in α phase of the aged samples exhibits moderate to high intensity along with {0001}||ND fibre. Non-basal textures in α phase have always weak/moderate intensity. The Vickers hardness values of the alloy increase from βSTWQ to all ageing temperatures due to precipitation hardening. The A2-550-4h sample exhibits no yielding due to fine α phase precipitates. On the other hand, A2-750-4h sample displays moderate elongation with high strength values. .