Twin Boundary Induced Grain Coarsening in Friction Stir Welding of Fine- and Ultra-Fine-Grained Commercially Pure Titanium Base Metals

The mechanical properties of commercially pure titanium can further be improved through the grain refinement processes; however, welding fine-grained materials is challenging due to coarsening in weld area and hence weakening locally. Meanwhile, friction stir a promising process which metallurgical bonding established solid-state mixing welded; no studies have reported ultra-fine-grained commercial purity date. In this research, (1.58 0.66 μm, respectively) was conducted. effect microstructural feature base metals on evolution zone feasibility for those were discussed. It found that fraction twin boundaries material higher than material. accelerated dynamic recrystallization recovery zone, inducing loss structure character after welding.