镁与热处理对Al-4Si-(xMg)合金导电性及力学性能的影响

利用SEM、XRD、EDS、硬度计及电阻率测试仪等方法分析Mg元素和不同热处理对Al-4Si-(xMg)(x=0~1.5%,质量分数)系列合金导电率及硬度的影响。结果表明:随Mg添加量增加,铸态合金的导电率和硬度先增后减,最佳添加量为1.1%。Mg使铸态合金硬度显著增加,但恶化了其导电率。Al-4Si-(xMg) 合金经不同热处理后,合金导电率大幅提高,硬度略有降低。其中,固溶时效对合金导电率的提高最显著,硬度降低幅度最小,使Al-4Si-1.1Mg合金导电率和硬度匹配关系最好。通过Mg元素和固溶时效的协同作用,可使铸态Al-4Si合金导电率由43.3%IACS提高至50.9%IACS,硬度由41.5 HV0.5增加至84.3 HV0.5。

Effect of magnesium and heat treatment on electrical conductivity and mechanical properties of Al-4Si-(xMg) alloys

Effects of Mg addition and different heat treatments on the electrical conductivity and hardness of Al-4Si-(xMg)(x=0-1.5%,mass fraction)alloys were analyzed by SEM,XRD,EDS,hardness tester and resistivity tester.The results show that for the as-cast alloys,the electrical conductivity and hardness increase first and then decrease with the increase of Mg addition and 1.1% is the optimum addition of Mg,while the Mg addition significantly improves the hardness,but damages the electrical conductivity.After different heat treatments,the electrical conductivity of Al-4Si-(xMg)alloys greatly increases and the hardness slightly decreases,where the solid solution+aging treatment significantly increase the electrical conductivity but reduce the hardness to the minimum,so that the Al-4Si-1.1Mg alloy has the best matching between electrical conductivity and hardness.Through the synergistic effect of Mg addition and solid solution+aging treatment,the electrical conductivity of the as-cast Al-4Si alloy can be improved from 43.3%IACS to 50.9%IACS,the hardness can be increased from 41.5 HV0.5 to 84.3 HV0.5.