Synergistic effect of solution-aging on phase evolution and high-temperature creep resistance in inertia-friction-welded Ti–6Al–4V aerospace components
Ying Li, Weiying Huang, Kefu Gan, Zibo Zhao, Yujing Liu, Danyang Liu, Libo Zhou, Jian Chen
Abstract
This study investigates the effects of a post-welding T6 heat-treatment strategy, namely solid solution and ageing treatment, on the microstructural evolution and high-temperature mechanical properties of Ti–6Al–4V (TC4) alloy joints produced by inertia friction welding (IFW). The results indicate that T6 treatment optimizes the α/β phase content in the weld joints and produces a basket-like microstructure with fine grain size and good thermal stability. After such a T6 treatment, the tensile strength of the TC4 weld joints at 500 °C is enhanced from ∼620 MPa to ∼670 MPa, and the steady-state creep rate highly decreases, e.g., it decreases to a value as low as ∼4.43 × 10 −8 s −1 under the testing condition of 500 °C/175 MPa. Moreover, the analysis using digital image correlation (DIC) method further demonstrates that the strain distribution along the weld joint turns much more homogeneous in the T6-treated sample, which suggests the better deformability of such weld joints. This study correlates the phase evolution caused by T6 heat treatment and the improved mechanical performance of the TC4 weld joints, and provides theoretical support for the reliable design of high-temperature titanium alloy weld joints in aerospace applications.