To investigate the superplastic deformation behavior of cryorolled Ti-6Al-4V titanium alloy,tensile tests were carried out at760℃and 830℃with different strain rate.The evolution of grain and micro structure has been...To investigate the superplastic deformation behavior of cryorolled Ti-6Al-4V titanium alloy,tensile tests were carried out at760℃and 830℃with different strain rate.The evolution of grain and micro structure has been studied using transmission electron microscopy and electron backscatter diffraction.When the tensile temperature was 760℃(<0.5T_(m),T_(m)is absolute melting point of alloy.)and the strain rate was 5×10^(-4)s^(-1),the fracture elongation of the sample reached 385%,showing good low-temperature superplasticity.Compared with the tensile temperature of 760℃,the fracture elongation of the s ample at 830℃was lower due to grain coarsening and oxidation.The strain rate sensitivity value m of all samples was larger than0.3,which confirmed that the cryorolled Ti-6A1-4V titanium alloy with a non-equiaxed grains structure can achieve high superplasticity at a temperature lower than 0.5T_(m),and indicated that the main deformation mechanisms in the tensile test at760-830℃were grain rotation and grain boundary sliding.After the tensile test,the average grain size of all samples was less than 5μm,in which significant dynamic recrystallization and recovery occurred.展开更多
基金financial support from the High-tech Industry Technology Innovation Leading Plan of Hunan Province(Grant No.:2020GK2032)the Research Fund of the Key Laboratory of High-Performance Complex Manufacturing at Central South University。
文摘To investigate the superplastic deformation behavior of cryorolled Ti-6Al-4V titanium alloy,tensile tests were carried out at760℃and 830℃with different strain rate.The evolution of grain and micro structure has been studied using transmission electron microscopy and electron backscatter diffraction.When the tensile temperature was 760℃(<0.5T_(m),T_(m)is absolute melting point of alloy.)and the strain rate was 5×10^(-4)s^(-1),the fracture elongation of the sample reached 385%,showing good low-temperature superplasticity.Compared with the tensile temperature of 760℃,the fracture elongation of the s ample at 830℃was lower due to grain coarsening and oxidation.The strain rate sensitivity value m of all samples was larger than0.3,which confirmed that the cryorolled Ti-6A1-4V titanium alloy with a non-equiaxed grains structure can achieve high superplasticity at a temperature lower than 0.5T_(m),and indicated that the main deformation mechanisms in the tensile test at760-830℃were grain rotation and grain boundary sliding.After the tensile test,the average grain size of all samples was less than 5μm,in which significant dynamic recrystallization and recovery occurred.
