Ultrafine-grained commercial-purity aluminum（AA1070） sheets produced by four cycles of accumulative roll-bonding（ARB） without lubrication are subjected to annealing treatments in the temperature range from 250℃ t...Ultrafine-grained commercial-purity aluminum（AA1070） sheets produced by four cycles of accumulative roll-bonding（ARB） without lubrication are subjected to annealing treatments in the temperature range from 250℃ to 400℃.Microstructures and microtextures in the surface and center regions of the ARBed and annealed sheets are measured by electron backscatter diffraction.The results show that annealing treatments at 325℃ or above lead to a reduction in the microstructure gradient but a significant through-thickness texture gradient different from that in the as-deformed state.The center region is featured by the development of a strong cube texture at the expense of rolling components.In the surface region,shear-type components are either enhanced or largely retained,showing a high persistency upon annealing.While the grain structures are restored predominantly by continuous recrystallization in the surface region,a mixture of continuous and discontinuous recrystallization is envisaged for the center region.展开更多
The effect of annealing temperature on the development of microstructure and texture in an c~＋/3 titanium alloy Ti-6.5AI-3.SMo-l.5Zr-0.3Si （TCll） preformed by hot working was investigated with the aid of electron b...The effect of annealing temperature on the development of microstructure and texture in an c~＋/3 titanium alloy Ti-6.5AI-3.SMo-l.5Zr-0.3Si （TCll） preformed by hot working was investigated with the aid of electron back-scattered diffraction and X-ray diffraction measurements. It is shown that considerable microstructure and texture heterogeneities were developed in the cross-section of the hot-worked rod due to the non-uniform deformation. Subsequent annealing at 940 ℃ and 990 ℃ led to homogeneous microstructures with globular a grains, whereas a typical lamellar ca＋β microstructure was obtained after annealing at 1040 ℃. In the latter case, the Burgers orientation relationship was well preserved between the two phases in a single colony. The a lamellar within a given colony depicted similar crystallographic orientations and the boundary a grains shared the orientation of one of the neighboring c~ lamellar. In contrast, subsequent annealing had very limited effect on the main features of the textures, indicating strong inheritance of the texture heterogeneity in annealing. It is thus crucial to control the hot working process in order to achieve a high level of texture homogeneity in the final parts.展开更多
基金supported by the National Natural Science Foundation of China (Nos.51571213 and 51271204)the Hunan Provincial Innovation Foundation for Postgraduate (No.CX2016B040)
文摘Ultrafine-grained commercial-purity aluminum（AA1070） sheets produced by four cycles of accumulative roll-bonding（ARB） without lubrication are subjected to annealing treatments in the temperature range from 250℃ to 400℃.Microstructures and microtextures in the surface and center regions of the ARBed and annealed sheets are measured by electron backscatter diffraction.The results show that annealing treatments at 325℃ or above lead to a reduction in the microstructure gradient but a significant through-thickness texture gradient different from that in the as-deformed state.The center region is featured by the development of a strong cube texture at the expense of rolling components.In the surface region,shear-type components are either enhanced or largely retained,showing a high persistency upon annealing.While the grain structures are restored predominantly by continuous recrystallization in the surface region,a mixture of continuous and discontinuous recrystallization is envisaged for the center region.
基金financial support of the National Basic Research Program of China(No.2007CB613803)
文摘The effect of annealing temperature on the development of microstructure and texture in an c~＋/3 titanium alloy Ti-6.5AI-3.SMo-l.5Zr-0.3Si （TCll） preformed by hot working was investigated with the aid of electron back-scattered diffraction and X-ray diffraction measurements. It is shown that considerable microstructure and texture heterogeneities were developed in the cross-section of the hot-worked rod due to the non-uniform deformation. Subsequent annealing at 940 ℃ and 990 ℃ led to homogeneous microstructures with globular a grains, whereas a typical lamellar ca＋β microstructure was obtained after annealing at 1040 ℃. In the latter case, the Burgers orientation relationship was well preserved between the two phases in a single colony. The a lamellar within a given colony depicted similar crystallographic orientations and the boundary a grains shared the orientation of one of the neighboring c~ lamellar. In contrast, subsequent annealing had very limited effect on the main features of the textures, indicating strong inheritance of the texture heterogeneity in annealing. It is thus crucial to control the hot working process in order to achieve a high level of texture homogeneity in the final parts.
