磷变质对Al-17.5Si-4.5Cu-1Zn-0.7Mg-0.5Ni变形合金初晶硅形貌与室温拉伸性能的影响

Effects of phosphorus modification on morphology of primary silicon particles and mechanical properties of wrought Al-17.5Si-4.5Cu-1Zn-0.7Mg-0.5Ni alloy

研究了磷变质对半连续铸造Al-17.5Si-4.5Cu-1Zn-0.7Mg-0.5Ni变形合金初晶硅形貌与室温拉伸性能的影响。结果表明:磷变质处理后,铸锭(直径100 mm)中初晶硅形核率增加、颗粒分布均匀,其心部初晶硅平均尺寸由未变质处理的37μm细化到19μm;铸态变质处理合金室温抗拉强度为265 MPa,T6状态抗拉强度为345 MPa;实现了大压下量热变形,热变形变质处理合金在T6状态下,抗拉强度达到383 MPa,伸长率为1.15%。

The effects of phosphorus modification on the morphology of primary silicon particles and mechanical properties of a wrought direct chill（DC） cast Al-17.5Si-4.5Cu-1Zn-0.7Mg-0.5Ni alloy were investigated.The results show that the addition of phosphorus increases the nucleation rate of primary Si in the billet（100 mm in diameter） leading to fine and uniform distribution of primary Si particles.The average size of the primary Si particles in the modified alloy in the central region of the billet is 19μm,comparing with that of 37μm in the unmodified alloy.The achieved ultimate tensile strength（UTS） of the modified alloy is 265 MPa in the as-cast state and 345 MPa in T6 condition.Hot deformation of modified and unmodified alloys with high per-pass reduction is carried out.The UTS and elongation of the hot-deformed modified alloy in T6 condition are 383MPa and 1.15%,respectively.