Deformation Mechanism of Powder Metallurgy Ti-45Al-7Nb-0.3W Alloy Rolling at High Temperature and Medium Strain Rate

The microstructure of Ti-45Al-7Nb-0.3W (mole fraction, %)alloy after high temperature medium strain rate pack rolling was studied by SEM and TEM.The results show that when the rolling temperature is 1270℃,the pass reduction is 30% and the total deformation reaches 83%,no obvious crack appears in the plate.A large number of deformed twins appear in the microstructure of the medium strain rate rolling plate.Some deformation twins even pass through adjacent grains to enter the next grain.A large number of β phases distributed at the grain boundaries are found, and significant dynamic recrystallization occurs.The deformation mechanism of lamellar structure is mainly deformed twinning and bending, the spheroidization of lamellar structure occurs in the strong bending region.The spheroidization of the lamella is the early characteristic of dynamic recrystallization.The deformation mechanism of Ti-45Al-7Nb-0.3W alloy at moderate strain rate rolling is twinning and dynamic recrystallization.