7050T7451铝合金厚板不同位置组织性能的差异

Study on properties and microstructure of 7050 aluminum alloy plate at different positions

通过拉伸性能、导电率、显微组织、化学成分、剥落腐蚀、显微硬度、织构分析和扫描电镜组织等检测手段,分析了板材厚度为80 mm的7050T7451铝合金不同厚度层以及同一厚度层不同方向的组织性能。结果表明,80 mm厚7050T7451铝合金板材在不同厚度的金相组织和力学性能存在显著的差异,在同一厚度的力学性能具有各向异性,且不同厚度处存在各向异性的差异不同;板材中心的纵向抗拉强度最大,且纵向、横向抗拉强度的差异最大;板材上下表层约6 mm深处的纵向抗拉强度最小,且比横向的抗拉强度要小,出现反常各向异性;板材中心层的合金元素含量最低,导电率及织构强度最高;1/4或3/4厚度处显微硬度最高,剥落腐蚀性能最好。

The microstructure and properties of 80 mm-thick 7050T7451 aluminum alloy plates were studied at different thickness layers and in different directions of the same thickness layer through tests and analysis of tensile properties,electrical conductivity,microstructure,chemical composition,exfoliation corrosion,microhardness,texture analysis and scanning electron microscopy.The results show that the microstructure and mechanical properties are obviously different at different thickness positions,the mechanical properties are anisotropic at the same thickness position,and the anisotropy are discrepant at different thickness positions.At the central position,the longitudinal tensile strength is maximum and the longitudinal and transverse tensile strength are most different.At the layers 6mm from the upper and lower surfaces,the longitudinal tensile strength is minimum,that is,the longitudinal tensile strength is lower than the transverse tensile strength,which is abnormal anisotropy.At the central layer,the content of elements is the lowest,and the conductivity and texture strength are the highest.At the 1/4 or 3/4 layers,the microhardness is the highest and the exfoliation corrosion resistance is the best.