True stress-true strain curve,microstructure and texture information were obtained to investigate the superplastic deformation behavior of 1420 Al-Li alloy sheets with initial elongated grains.From the true stress-tru...True stress-true strain curve,microstructure and texture information were obtained to investigate the superplastic deformation behavior of 1420 Al-Li alloy sheets with initial elongated grains.From the true stress-true curve,the stress increases with the increase of strain to 0.15,then dramatically decreases with the increase of strain to 0.80,and finally keeps almost a horizontal line.Meanwhile,initial elongated grains are gradually changed into equiaxed grains and the initial strong Brass {0 1 1} <2 1 1> and S {1 2 3} <6 3 4> orientations are turned into nearly random orientation with increasing strain.All these results suggest that dislocation activity is the dominant mechanism during the first stage,then dynamic recrystallization occurs,and grain rotation is expected as an accommodation for grain boundary sliding(GBS).At larger strains,grain boundary migration(GBM) becomes necessary to accommodate GBS.展开更多
Effect of trace rare earth Er addition on the aging behavior of 1420 alloys was studied using hardness testing. Precipitation behavior during aging was investigated by electron microscopy transmission. It is found tha...Effect of trace rare earth Er addition on the aging behavior of 1420 alloys was studied using hardness testing. Precipitation behavior during aging was investigated by electron microscopy transmission. It is found that small amounts of Er can modify the aging behavior of 1420 alloy, for example, improve the hardness and shift peak aging time. All those results may be attributed to the increase of diffusion coefficient of Li atom in the Al matrix added with Er. As a consequence, rate of nucleation and growth of δ′ (Al_3Li) was promoted; the Al_3Er particles act as preferential sites for the nucleation and growth of δ′, which in turn results in the presentation of more composite particles.展开更多
基金Project(2006DFA53250) supported by the International Science and Technology Cooperation Program of ChinaProject(2005CB623706) supported by the National Basic Research Program of China
文摘True stress-true strain curve,microstructure and texture information were obtained to investigate the superplastic deformation behavior of 1420 Al-Li alloy sheets with initial elongated grains.From the true stress-true curve,the stress increases with the increase of strain to 0.15,then dramatically decreases with the increase of strain to 0.80,and finally keeps almost a horizontal line.Meanwhile,initial elongated grains are gradually changed into equiaxed grains and the initial strong Brass {0 1 1} <2 1 1> and S {1 2 3} <6 3 4> orientations are turned into nearly random orientation with increasing strain.All these results suggest that dislocation activity is the dominant mechanism during the first stage,then dynamic recrystallization occurs,and grain rotation is expected as an accommodation for grain boundary sliding(GBS).At larger strains,grain boundary migration(GBM) becomes necessary to accommodate GBS.
文摘Effect of trace rare earth Er addition on the aging behavior of 1420 alloys was studied using hardness testing. Precipitation behavior during aging was investigated by electron microscopy transmission. It is found that small amounts of Er can modify the aging behavior of 1420 alloy, for example, improve the hardness and shift peak aging time. All those results may be attributed to the increase of diffusion coefficient of Li atom in the Al matrix added with Er. As a consequence, rate of nucleation and growth of δ′ (Al_3Li) was promoted; the Al_3Er particles act as preferential sites for the nucleation and growth of δ′, which in turn results in the presentation of more composite particles.
