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 (Vc) on microstructural evolution. Higher Vc 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.
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