Characterization and modeling of room-temperature high compressive stress creep in near-α titanium alloy joints

Titanium and its alloys can creep under high external stress at room temperature conditions, posing a significant threat to the safety of welded structures due to the emergence of room temperature creep as a weak point in the structure. This paper delves into the deformation characteristics and microstructural transformations of 60 mm thick TA31 titanium alloy narrow gap tungsten inert gas welded joint subjected to a compression stress of 990 MPa for 240 h. A comparative analysis is performed on the alterations in microstructure, grain orientation, and microhardness of both the weld metal and the heat-affected zones before and after creep. This analysis reveals the impact of creep on the microstructure and grain orientation of the welded joints, elucidating the reasons behind the reduction in microhardness post-creep. Furthermore, the paper elucidates the disparities in creep response behavior and mechanisms between the weld metal and the heat-affected zones under high-stress compression at room temperature. These insights provide a foundation for enhancing structural design, optimizing welding procedures, and enhancing the reliability of joint creep performance in the future.