Na、Sb对亚共晶Al-Si合金变质效果的影响

Influence of Na and Sb on Modification Effect of Hypolutectic Al-Si Alloy

通过在亚共晶Al Si合金中分别加入Na、Sb变质剂,保温1～5h,重熔1～3次,对其显微组织及力学性能进行了比较研究。结果表明,随保温静置时间的延长,两种变质的共晶硅长度都增大,拉伸强度和延伸率都下降,但是Na变质远大于Sb变质的共晶硅长度,Sb变质的拉伸强度和延伸率均大于Na变质;随重熔次数增多,Na变质的共晶硅长度、力学性能基本不变,而Sb变质的共晶硅长度增大,力学性能下降,但是共晶硅长度远小于Na变质,力学性能均大于Na变质,说明Sb变质衰退缓慢,有良好的重熔性。

After holding temperature time for 1～5 hours and rewelting for 1～3 times, the microstructures and mechanical properties of AlSi hypolutectic alloy are investigated and compared by adding respectively alterants of Na or Sb into the alloy. The experimental results show that with the prolonging of static holding temperature time the lengths of two kinds of modificated eutectic silicon in the alloy increased,and both the tensile strength and extensive ratio decreased,but the length of eutectic silicon modificated by Na is much larger than by Sb,and the mechanical properties of the alloy modificated by Sb are higher than by Na;with the increase of the times of rewelting,the length of eutectic silicon and the mechanical properties of the alloy after modification of Na remain no change,whereas the length of eutectic silicon modificated by Sb increased and the mechanical properties decreased,but the length of eutectic silicon is far shorter than that modificated by Na and mechanical properties are better than that modificated by Na.This indicates that the degradation of Sb modification is slower than others,and Sb has good rewelting property.