摘要
It is found that tensile flow curves of samples of annealed ultrafine-grained aluminum AA1090 show the development of a yield point and a significant mechanical anisotropy.To rationalize the anisotropic tensile behavior,the orientation data of the annealed material were measured using electron backscatter microscopy.It is found that the inferior mechanical properties of samples tested at 45°to the rolling direction may be attributed to a strong rolling texture effect and that the anisotropic magnitude of the yield drop may be related to the proportion of grains with soft orientations(defined as those with Schmid factor greater than 0.45)in the sample.Additionally,it is found that the anisotropy in tensile ductility is in general agreement with a Considère criterion analysis and that the mechanical anisotropy in the samples is only partly explained by the crystallographic texture,where microstructural anisotropy may also play a role.
经退火处理的超细晶纯铝AA1090在拉伸试验中表现出明显的屈服点现象及力学性能的各向异性。为进一步解释该材料的拉伸性能各向异性,利用电子背散射衍射技术对退火处理后材料的取向信息进行分析。结果表明,沿与轧制方向成45°的拉伸试样所呈现出的较差的力学性能归因于强轧制织构的作用,并且各方向屈服下降的程度与试样中软取向晶粒(Schmid因子>0.45)的百分比相关。另外,伸长率的各向异性大致符合Considère准则;运用晶体学织构只能解释部分的力学性能各向异性行为,同时还需考虑显微组织结构各向异性的作用。
基金
Project(50971074)supported by the National Natural Science Foundation of China
