Ultrafine-grained commercial pure titanium (CP Ti) offers a superior strength-ductility balance for aerospace and biomedical applications, but conventional grain refinement often compromises integrity and efficiency. This study investigated cryogenic temperature large strain extrusion machining (CT-LSEM) to examine the effects of cutting speed (V c) on microstructural evolution. Higher V c promoted grain refinement and enhanced hardness and yield strength. EBSD revealed a 7% increase in dislocation density and formation of 10–12, 11–22, and 11–21 twins. Strengthening arose from fine-grain, dislocation, and twin-boundary mechanisms. These findings clarify the coupled effects of speed and cryogenic temperature on CP Ti microstructure, providing insights for high-performance, efficient processing.
Zhong et al. (Mon,) studied this question.