Conventional rolling experiments via the embedded pin in rolling sheet method were carried out at different reduction rates,starting rolling temperatures,and rolling speeds,and the effects of rolling parameters(i.e.,t...Conventional rolling experiments via the embedded pin in rolling sheet method were carried out at different reduction rates,starting rolling temperatures,and rolling speeds,and the effects of rolling parameters(i.e.,temperature,equivalent strain,and rolling time)on dynamically recrystallized(DRX)microstructures of AZ31 alloy during hot rolling were studied quantitatively.The temperature-strain dependence of the high-angle grain boundary fraction(HAGB%)was examined through electron backscattered diffraction.Results showed that as-rolled microstructures with high HAGB%may be obtained under average rolling temperatures of 270-320℃,equivalent strains higher than 0.8,and a rolling speed of 246 mm/s.These results may be related to the DRX kinetics and dynamic recovery which are controlled by deformation temperature and strain.HAGB%decreased with increasing rolling time(decreasing rolling speed),which is attributed to dynamic recovery,and the recrystallized grain size decreased as rolling time increased.However,further increases in rolling time increased average grain sizes but decreased mean subgrain sizes;these results are attributed to increases in the low-angle grain boundary(LAGB)length per unit area with rolling time.LAGB formation was controlled by dynamic recovery,which consistently follows polygonization or formation of new subgrains inside larger grains;hence,average subgrain sizes decreased with the rolling time.The effect of dynamic recovery on HAGB and LAGB formation and their related mechanisms over a wide range of strains and temperatures were discussed in detail.展开更多
In order to obtain quantitative relationship between（0002） texture intensity and hot rolling conditions, conventional rolling experiments on AZ31 magnesium alloys were performed with 20%-40% reductions and temperatu...In order to obtain quantitative relationship between（0002） texture intensity and hot rolling conditions, conventional rolling experiments on AZ31 magnesium alloys were performed with 20%-40% reductions and temperatures within the range of 300-500 ℃. Shear strain and equivalent strain distributions along the thickness of the rolled sheets were calculated experimentally using embedded pin in a rolling sheet. Rolling microstructures and textures in the sheet surface and center layers of the AZ31 alloys were measured by optical microscopy（OM）, X-ray diffractometry（XRD） and electron back scatter diffraction（EBSD）. Effects of the rolling strain, dynamic recrystallization（DRX） and twinning on the texture evolution of the AZ31 alloys were investigated quantitatively. It is found that the highest（0002） basal texture intensities are obtained at a starting rolling temperature of 400 ℃ under the same strain. Strain–temperature dependency of the（0002） texture intensity of the AZ31 alloy is derived.展开更多
基金This work was supported by the National Science Foundation for Young Scholars of China.(Grant No.51401043).
文摘Conventional rolling experiments via the embedded pin in rolling sheet method were carried out at different reduction rates,starting rolling temperatures,and rolling speeds,and the effects of rolling parameters(i.e.,temperature,equivalent strain,and rolling time)on dynamically recrystallized(DRX)microstructures of AZ31 alloy during hot rolling were studied quantitatively.The temperature-strain dependence of the high-angle grain boundary fraction(HAGB%)was examined through electron backscattered diffraction.Results showed that as-rolled microstructures with high HAGB%may be obtained under average rolling temperatures of 270-320℃,equivalent strains higher than 0.8,and a rolling speed of 246 mm/s.These results may be related to the DRX kinetics and dynamic recovery which are controlled by deformation temperature and strain.HAGB%decreased with increasing rolling time(decreasing rolling speed),which is attributed to dynamic recovery,and the recrystallized grain size decreased as rolling time increased.However,further increases in rolling time increased average grain sizes but decreased mean subgrain sizes;these results are attributed to increases in the low-angle grain boundary(LAGB)length per unit area with rolling time.LAGB formation was controlled by dynamic recovery,which consistently follows polygonization or formation of new subgrains inside larger grains;hence,average subgrain sizes decreased with the rolling time.The effect of dynamic recovery on HAGB and LAGB formation and their related mechanisms over a wide range of strains and temperatures were discussed in detail.
基金Project(51401043)supported by the National Natural Science Foundation of China
文摘In order to obtain quantitative relationship between（0002） texture intensity and hot rolling conditions, conventional rolling experiments on AZ31 magnesium alloys were performed with 20%-40% reductions and temperatures within the range of 300-500 ℃. Shear strain and equivalent strain distributions along the thickness of the rolled sheets were calculated experimentally using embedded pin in a rolling sheet. Rolling microstructures and textures in the sheet surface and center layers of the AZ31 alloys were measured by optical microscopy（OM）, X-ray diffractometry（XRD） and electron back scatter diffraction（EBSD）. Effects of the rolling strain, dynamic recrystallization（DRX） and twinning on the texture evolution of the AZ31 alloys were investigated quantitatively. It is found that the highest（0002） basal texture intensities are obtained at a starting rolling temperature of 400 ℃ under the same strain. Strain–temperature dependency of the（0002） texture intensity of the AZ31 alloy is derived.
