Role of Stress-Induced Martensite Transformation on Deformation Behavior and Microstructural Evolution in Metastable β Titanium Alloys during Compressive Deformation

In this paper, in order to investigate the effect of stress-induced martensitic transformation (SIMT) on the deformation behavior and microstructure evolution of metastable β titanium alloy, the β solution treated Ti-10 V-2Fe-3Al (Ti-1023) alloy was compressed at room temperature and its deformation behavior was analyzed. Optical microscopy (OM) and electron backscatter diffraction (EBSD) were used to study the microstructure evolution of alloys at different strain. The results show that the various deformation mechanisms have been presented in the stress-strain curve and strain hardening rate curve of the Ti-1023 alloy different during the compression deformation, respectively, and the SIMT gradually activated (ε < 5%). There are significant changes in the content and morphology of α″-martensite due to the SIMT and deformation induced martensitic twinning (DIMT) gradually activated with the strain increasing, which the α″-martensite segmented continuously into smaller grain sizes (~ 6 μm) leading to grain refinement strengthening effect. Simultaneously, there is specific orientation relationships (SORs) between β-matrix and α″-variants with < 100 > _β // <100 > _α″, < 110 > _β // <010 > _α″, and < 110 > _β // <001 > _α″. Moreover, the average values of kernel average misorientation (KAM) and geometrically necessary dislocations (GNDs) significantly increased, indicating that the SIMT and DIMT activated continuously with a high volume fraction of α″-martensite would lead to higher dislocation density.