Microstructure evolution and crystallographic slip modes during grind hardening in TC21 titanium alloy

In this work, the microstructure evolution and slip mechanism of TC21 titanium alloy in grind hardening (GH) and grind hardening and aging treatment (GHAG) were comparatively investigated. The experimental results showed that the hardened layer formed in both GH and GHAG is mainly composed of TiN, while their internal microstructure is quite different. Compared with as-received alloy, the tensile strength and elongation after GH process increased by 110 MPa and 1.5%, respectively. The tensile strength after GH process increased by 50 MPa but the elongation decreased by 0.2%. Moreover, A method to deduce slip systems by using interior crystall misorientation axis (ICMA) was demonstrated in this paper. The distribution of ICMA indicated that three major slip systems were activated which was verified by texture components in ODF sections. The slipping results in two kinds of crystal orientation distribution: (a) the activated slip plane parallel to loading stress; (b) the slip direction parallel to loading stress, but existing a deviation angle between slip plane and loading stress.

Automated summary

In this study, microstructure evolution and slip mechanism of TC21 titanium alloy in grind hardening and aging treatment were investigated, showing that the hardened layer mainly consisted of TiN. Tensile strength and elongation increased after grind hardening process, with different effects observed in grind hardening and aging treatment. The study also demonstrated a method to deduce slip systems using interior crystall misorientation axis, identifying three major slip systems.