汽车用6061铝合金板轧制变形组织及力学性能分析

Analysis of Rolling Deformation Microstructure and Mechanical Properties of 6061 Aluminum Alloy Plate for Automobile

通过显微组织观察、拉伸性能测试、应力分布分析研究了6061铝合金板材在厚度上显微组织、织构及其力学性能的关系。结果表明:在板材厚度上形成不均匀组织,表层存在许多亚晶;在1/4层形成大尺寸再结晶晶粒;中心层晶粒数量显著增加。从板材的表层到中心层,屈服强度与抗拉强度先减小后增大,并且在1/4层位置达到最小。从心部到表层,轧制织构比例不断减小,剪切织构在1/4层最高,厚板中心层再结晶织构很低。第1道次轧制在5s时被咬入轧辊,此时每层都受到正剪切应力,同时1/4层受到的剪切应力高于表层;当轧制道次增加后,板材厚度降低,每层剪切应力都发生小幅变化。

The relationship between microstructure, texture and mechanical properties of 6061 aluminum alloy plate in thickness was studied by means of microstructure, tensile properties and stress distribution. The results show that the uneven microstructure is formed in the thickness of the plate, and there are many subcrystals on the surface layer. A larger recrystallized grain is formed on the 1/4 layer. The number of the central layer grains is significantly increased. When the surface layer of the plate is transitioned to the central layer, the yield strength and tensile strength decrease first and then increase, and reach the minimum in the position of 1/4 layers. In the process of transition from the center to the surface, the proportion of rolling texture decreases continuously, the shear texture is the highest in 1/4 layers, and the recrystallized texture in the center layer of thick plate is very low. The first pass of rolling is nipped into the roll at 5 s. At this time, each layer is subjected to positive shear stress, and the shear stress of 1/4 layer was higher than that of the surface layer. When the rolling pass increases, the thickness of the sheet decreases,and the shear stress of each layer changes slightly.