热处理工艺对Sr变质Al-11.6Si-0.5Mg合金组织与性能的影响

Effect of Heat Treatment on Microstructure and Performance of Al-11.6Si-0.5Mg Alloy Modified by Strontium

在铸造Al-11.6Si-0.5Mg合金中,加入Sr作为变质剂,并研究了T6热处理工艺对其组织与性能的影响。结果表明:0.3%Al-8Sr中间合金能有效细化α-Al枝晶与共晶组织;T6热处理的最佳经济型工艺为535℃固溶6 h,50～60℃水冷;160℃时效6 h,空冷。Sr变质与T6热处理后,合金的力学性能显著提高,抗拉强度由变质前的183 MPa提高至348 MPa,伸长率由3.0%提升至6.5%左右。

Strontium （St） was added as modifier when the AI-11.6Si-0.5Mg alloy was casted and the effects of T6 heat treatment on microstructure and performance of alloy were also investigated. The results show： the 0.3% Al-8Sr master alloy can refine effectively the a-Al dendrite and eutectic structure; the best economic process of T6 heat treatment is solution at 535 ℃ for 6h; and then water cooling at 50 ℃-60 ℃; aging at 160 ℃ for 6 h, then air cooling. After Sr modification and T6 heat treatment, the mechanical properties of alloy are improved remarkably, the tensile strength increases by 348 MPa from 183 MPa before modification and the elongation raises from 3.0% to 6.5%.