New insight into deformation mechanism for a low-cost titanium alloy during isothermal compression

A new type of low-cost titanium alloy TC32 has amazing ability to prevent forging cracking during rapid deformation. The SEM, TEM/HRTEM, TKD are applied to reveal the intrinsic reasons for its good plasticity. Compared to a slower strain rate, microstructure of TC32 alloy shows a very special morphology after hot deformation at a higher strain rate. A considerable number of infrequent stripes with 20–30 nm scale within the α phase are found, and it is considered to be the key to improving plasticity. The elongated diffraction spots and the atomic arrangement characterized by folding line confirm that the stripe structure has the feature of stacking fault (SF). In addition, further crystallographic characterization confirms the existence of nanotwins, mainly the single {10−11}< 10–12 > compression twins. The SFs is the precursor of nanotwins and coexist with them. The symbiotic SFs/nanotwins are capable of absorbing energy during plastic deformation, improving the resistance to cracking.