Effect of rotationally accelerated shot peening on the microstructure and mechanical behavior of a metastable β titanium alloy

Microstructural evolution and deformation mechanism of a metastable beta alloy (Ti-10V-2Fe-3Al) processed by rotationally accelerated shot peening (RASP) were systematically investigated with optical microscopy, X-ray diffraction, electron backscatter diffraction and transmission electron microscopy. Different gradient hierarchical microstructures (gradients in alpha '' martensite and beta phase, and hierarchical twins range from the nanoscale to microscale) can be fabricated by RASP via changing the shot peening time. The hardening behavior and tensile mechanical properties of gradient hierarchical microstructure were systematically explored. Novel deformation twinning systems of {112} (alpha '') and {130}< 310 > (alpha '') in the kinked alpha '' martensite were revealed during the tensile deformation. It was found that stress-induced martensitic transformation, twinned alpha '' martensite and the related dynamic grain refinement contribute to hardness and work hardening ability. Simultaneous improvement of strength and ductility of the metastable beta titanium alloy can be achieved by introducing a gradient hierarchical microstructure. (C) 2021 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Automated summary

The microstructural evolution and deformation mechanism of a metastable beta alloy processed by rotationally accelerated shot peening were systematically investigated, revealing the formation of different gradient hierarchical microstructures. Novel deformation twinning systems in the martensite were observed during tensile deformation, contributing to hardness and work hardening ability. Introducing a gradient hierarchical microstructure can simultaneously improve the strength and ductility of the metastable beta titanium alloy.