Effect of Mo content and strain rate on compressive deformation mechanisms in Ti-xMo-2Fe alloys

The effects of Mo content and strain rate on the deformation mechanisms and stress-induced phase transformations in β-Ti alloys are investigated using alloys containing 3.4, 5.0, and 9.2 wt.% Mo, along with 2 wt.% Fe, fabricated by vacuum arc remelting and subjected to compression test at strain rates of 1.0×10 -3 , 1.0×10 -1 , and 3.3×10 3 s -1 . The phase and microstructural evolutions are characterized using X-ray diffraction and electron backscatter diffraction. At low strain rates, the stress-induced α″ martensitic transformation dominates, particularly in alloys with lower Mo content. With increasing strain rate, the α″ formation is suppressed, and deformation twinning, dislocation slip, and localized dynamic recrystallization emerge as the dominant mechanisms. The transition in deformation behavior is governed by the stability of the β phase, which modulates both the driving force and kinetics of the phase transformation. These findings offer insights into the rate-dependent mechanical behavior of Ti-xMo-2Fe alloys.