Compressive deformation-induced hierarchical microstructure in a TWIP β Ti-alloy

The deformation mode of {332}<113> twinning (hereafter called 332T) has often been observed under the plastic flow in metastable β titanium alloys with body-centered cubic (BCC) structure, which contributes to improving the mechanical performance. Herein, we report a structure of compressive deformation-induced primary 332T with hierarchical and/or heterogeneous composite sub-structure in a Twin-Induced Plasticity (TWIP) β Ti-alloy under uniaxial compression. The detailed structural characterization after compressive deformation revealed that the sub-structure, including secondary 332T and secondary {112}<111> twinning, formed inside the 332T structure, which constitutes a hierarchical and/or heterogeneous structure at micro- and nano-scale and consequently contributes to the high strength, large ductility and enhanced strain-hardening behavior.