用非晶合金细化变质处理A356铝合金的显微组织和力学性能

摘要

A356 aluminum alloy with Al-5Ti-1B pre-refine treatment was modified by adding various amounts of Zr56 Co22 Al16 Ag6 amorphous alloy ribbons,and then solid solution and aging heat treatment was executed on the aluminum alloy.The microstructure and mechanical properties of the aluminum alloy were studied, and the amorphous ribbon′s refine mechanism was also discussed.The results show that with the increase of amorphous alloy ribbon′s adding amounts,grain size and the secondary dendrite spacing of the aluminum alloy all decrease,and the mechanical properties of the aluminum alloy are improved.Dispersed granular Al3 Zr phase is found in eutectic structure,the phase increases the number of nucleus,hence refines the grains.Adding 0.4wt% Zr56 Co22 Al16 Ag6 amorphous alloy ribbons and setting incubation period of 10 min could make the aluminum alloy obtain the best refining effect,and after solid solution and aging treatment,tensile strength and elongation of the aluminum alloy owned the higher mechanical properties,compared with the aluminum alloy without adding amorphous ribbons,its tensile strength and elongation increased by 7%and 64.4%,respectively.%通过添加不同量的Zr56 Co22 Al16 Ag6非晶合金条带对用Al-5Ti-1B预细化的A356铝合金进行细化变质处理,然后再进行固溶时效热处理,研究了合金的显微组织和力学性能,并探讨了非晶合金的细化强化机制.结果表明：随着非晶合金添加量的增加,铝合金的晶粒尺寸和二次枝晶间距均逐渐减小,力学性能得到了提高；铝合金的共晶组织中出现了弥散分布的颗粒状 Al3 Zr 相,该相作为非均质形核的核心,起到细化晶粒的作用；加入质量分数为0．4％的非晶合金,并设定孕育期为10 min,铝合金可获得最佳的细化效果,其经固溶时效处理后的抗拉强度和伸长率比未加入非晶合金的分别提高了7％和64．4％.