Tailoring hierarchical deformation mechanisms in metastable β titanium alloy via heterogeneous lamellar β structure design

The deformation mechanism of Ti-7Mo-3Nb-3Cr-3Al alloy was tailored by constructing heterogeneous lamellar β structure. This structural design induces hierarchical mechanism and thereby enhances work hardening and ultimate strength. During the initial deformation stage, α″ martensite and type I twins are activated. With increasing strain, {332}<113 > twins and stress-induced ω phase emerge along martensitic boundaries, forming a unique laminated deformation structure. Simultaneously, secondary martensite and β twins form within the β matrix, refining the matrix and hindering dislocation motion. This work provides novel insights into tailoring deformation behavior of metastable β titanium alloys.