CAJ | 학술논문

采用光学显微镜、扫描电镜、透射电镜、X射线衍射、常温拉伸和紧凑拉伸实验,对120 mm厚的7050铝合金板材的织构分布、拉伸性能及断裂韧性进行分析.结果表明:沿板材厚度方向,合金的组织、织构、强度及断裂韧性呈不均匀分布;在同一厚度处,合金的强度和断裂韧性具有明显的各向异性;由板材表层到中心,粗大第二相及再结晶晶粒尺寸逐渐增大;板材表层的织构主要由剪切织构{111}<110>和立方织构Cube{001}<100>组成,中心主要由β取向轧制织构和少量立方织构组成,1/4厚度处是过渡层;由板材表层到中心,轧向及长横向强度呈不均匀变化,板材中心处强度比表层的小;板材同一厚度处,强度和断裂韧性具有明显的各向异性,轧向强度大于长横向和短横向强度,L-T取向的断裂韧性大于T-L取向和S-L取向的断裂韧性;L-T取向的断裂方式主要是穿晶断裂,S-L取向的断裂方式以沿晶断裂为主,T-L取向是混合型断裂,其穿晶断裂比例比L-T取向的穿晶断裂比例小, 沿晶断裂比例比S-L取向的沿晶断裂比例小.
채용광학현미경、소묘전경、투사전경、X사선연사、상온랍신화긴주랍신실험,대120 mm후적7050려합금판재적직구분포、랍신성능급단렬인성진행분석.결과표명:연판재후도방향,합금적조직、직구、강도급단렬인성정불균균분포;재동일후도처,합금적강도화단렬인성구유명현적각향이성;유판재표층도중심,조대제이상급재결정정립척촌축점증대;판재표층적직구주요유전절직구{111}<110>화립방직구Cube{001}<100>조성,중심주요유β취향알제직구화소량립방직구조성,1/4후도처시과도층;유판재표층도중심,알향급장횡향강도정불균균변화,판재중심처강도비표층적소;판재동일후도처,강도화단렬인성구유명현적각향이성,알향강도대우장횡향화단횡향강도,L-T취향적단렬인성대우T-L취향화S-L취향적단렬인성;L-T취향적단렬방식주요시천정단렬,S-L취향적단렬방식이연정단렬위주,T-L취향시혼합형단렬,기천정단렬비례비L-T취향적천정단렬비례소, 연정단렬비례비S-L취향적연정단렬비례소.
The texture distribution, tensile property and fracture toughness of 7050 aluminum alloy thick plate were investigated by optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffractometry, tensile and toughness tests. The results show that the microstructure,texture,tensile property and fracture toughness are inhomogeneous in different layers along the thickness direction. At the same thickness, the tensile property and fracture toughness show appreciable anisotropy. From the surface to the center, the average sizes of the coarse second phase particles and recrystallization grains increase. Near the surface of the plate,typical shear textures {111}<110> and cube textures {001}<100> are observed, while the center of the plate shows typical β fiber texture with a scattering of cube texture. The quarter layer of the plate seems to serve as a transition layer. From the surface to the center, the strength is inhomogeneous in the rolling direction and long transverse direction. The strength in the center is smaller than that on the surface of the plate. The strength and fracture toughness show appreciable anisotropy at the same thickness. The strength in the rolling direction is higher than that in the long transverse direction and the short transverse direction, and the fracture toughness in the L-T orientation is higher than that in the T-L and S-L orientations at the same thickness. The fracture mode in the L-T orientation is trangranular fracture, and in the S-L orientation the fracture mode is intergranular fracture. In the T-L orientation, the fracture mode is a mixed fracture, the fraction of the trangranular fracture is lower than that in the L-T orientation, and the fraction of the intergranular fracture is lower than that in the S-L orientation.