【摘要】 对汽车用高强韧压铸Al-5Mg-2Si-Mn合金的微观组织和力学性能进行了研究。结果表明,Al-5Mg-2Si-Mn合金压铸组织主要包括:枝晶和颗粒状的大尺寸α1-Al晶粒,细小圆整的α2-Al晶粒以及[Al+Mg2Si]共晶区,共晶区比例约为30%。压铸件存在组织不均匀性,在铸件的表面观察到厚度为50~80μm的表面层,在表面层与内部组织之间则被表面边界层分开。压铸圆棒试样的铸态抗拉强度、屈服强度和伸长率分别达到350 MPa,204 MPa和13.8%,断口上则存在大量的解理台阶结构。更多还原

【Abstract】 In this paper, microstructure and mechanical properties of high toughness die cast Al-5Mg-2Si-Mn alloy, which is used in automobiles, were studied. The results indicate that microstructure of Al-5Mg-2Si-Mn alloy consists of coarse dendritic/spherical α1-Al grains, fine size α2-Al grains and [Al+Mg2Si] eutectic region.Volume fraction of the eutectic region is about 30%. The microstructure of die castings is un-uniform, and the surface layer is observed and its thickness is ranged from 50 μm to 80 μm. Moreover, surface layer and the inner region are separated by the surface boundary layer. Tensile strength, yield strength and elongation of rounded test-bars die castings are 350 MPa, 204 MPa and 13.8% respectively. Numerous cleavage steps are observed in the tensile fracture surface.更多还原