Fracture Toughness of Ti–15V–3Cr–3Sn–3Al Titanium Alloy in Different Heat-Treated Conditions

Abstract

Ti–15V–3Cr–3Sn–3Al (Ti–15–3) is a metastable β titanium alloy and is used in lightweight structures and gas storage tanks for aerospace applications. Tensile properties and fracture toughness (FT) of material are the significant inputs to the designer for finite-element analysis of structures. Fracture toughness data for Ti–15–3 alloy in different heat-treated conditions are not available. Hence, the present study is to evaluate the FT and tensile properties of Ti–15–3 alloy in different heat-treated conditions, namely solution treatment (ST) at 800 °C/30 min/AC, ST followed by aging at 538 °C/8 h/AC (say A1) and ST followed by aging at 482 °C/16 h/AC (say A2). The increase in tensile yield strength noticed in A1 and A2 conditions with respect to ST condition was 47% and 74%, respectively. The decrease in elongation (%) noticed in A1 and A2 conditions with respect to ST condition was 61% and 80%, respectively. Similarly, the decrease in FT values in A1 and A2 conditions with respect to ST condition was 43% and 57%, respectively.