Microstructural characterization and wear performance of shot-peened TA15 titanium alloy fabricated by SLM

Abstract

Ti-6Al-2Zr-1Mo-1 V (TA15) is a kind of near-α titanium alloy widely used in the aerospace industry, known for its excellent thermal strength and weldability. However, its low thermal conductivity and high deformation resistance make traditional machining methods challenging. Despite some researchers have manufactured TA15 alloy using SLM, the issue of tensile residual stresses on component surfaces remains prominent. This study aims to investigate the impact of shot peening on the surface residual stresses, microstructure, and wear performance of SLM-formed TA15 alloy. Experimental results demonstrate the successful introduction of surface compressive residual stresses through shot peening, with a maximum value of -897 MPa (at 0.45mmA intensity). Shot peening reduces the grain size within the deformation layer, resulting in a significant presence of dislocation entanglement and dislocation cells. When the intensity reaches 0.35mmA, the emergence of nanocrystals is observed, attributed to the influence of dislocation activity and dynamic recrystallization. Additionally, shot-peened samples exhibit notably improved wear resistance compared to their non-peened counterparts. However, excessive shot peening intensity may compromise surface quality. Therefore, under specific load conditions, higher intensity is not necessarily better. In conclusion, shot peening proves to be an effective technique for enhancing the surface stress state and wear performance of SLM-formed TA15 alloy.