High strength and ductility of pure titanium via twin-structure control using cryogenic deformation

We controlled the twin structure in pure Ti by deforming it at cryogenic temperature (∼77 K). Numerous thin individual twins were formed in the grains, thereby enabling strong twinning-induced grain refinement. The processed material had an ultrafine-grained microstructure, which greatly increased its strength. Notably, the ductility did not decrease significantly, despite the considerable strengthening, leading to superior tensile properties. This remarkable phenomenon occurred because the twin structure and the relatively small number of dislocations in the processed material enabled high resistance to necking instability. Our finding offers a new microstructural engineering method to achieve excellent tensile properties in pure Ti.