Local deformation mechanisms of two-phase Ti alloy

Jun, Tea Sung; Sernicola, Giorgio; Dunne, Fionn P.E.; Britton, T. Benjamin

Materials Science and Engineering A 649 (2016)

This paper describes a study of local deformation mechanisms in two-phase Ti alloy, Ti-6Al-2Sn-4Zr-2Mo, by performing in-situ micropillar compression tests. A colony microstructure was examined and select grains identified for examination were chosen with EBSD measurements. These grains were chosen to isolate individual slip systems within each test. Micropillars of tri-crystal (α-β-α) structure were fabricated from four determined regions, and compression tests were performed using a displacement-controlled nanoindenter set inside a SEM, with a constant displacement rate. The results show that the α/β morphology significantly affects the local deformation behaviour. For these colony structures, Schmid’s law in general enables anticipation of local slip activity, but the presence and morphology of the β phase can significantly alter the apparent yielding point and work hardening response. The role of interfaces within these tri-crystal pillars is discussed.