添加Ce与P+Sr复合变质对高硅耐热铝合金组织与性能的影响

Effect of Ce and Compound Modification of P+Sr on Microstructure and Properties of High Silicon Resist-heat Aluminum Alloy

研究了添加Ce与P+Sr复合变质对Al-21Si-1．5Cu-0．5Mg-2．5Fe合金显微组织与性能的影响。结果表明:添加1．5％Ce使粗大针状铁相消失,形成富Ce富Fe的鱼骨状相;P+Sr复合变质可使初晶硅平均尺寸由70 mm细化到20mm,共晶硅平均截线长降到2．1 mm,合金室温抗拉强度比未变质前提高21．5％,与P+Sr+Ce复合变质的Al-21Si-1．5 Cu-1．5Ni-2．5Fe-0．5Mg合金相当。

The effect of addition of Ce and compound modification on microstructure and properties of as-cast Al-21Si-1.5Cu-1.5Ni-2.5Fe-0.5Mg alloy was investigated. The results show that the gross heedle-like rich-Fe phase disappears and the fish-bone-like rich-Ce and rich-Fe phase emerges by addition of 1.5%Ce; the average dimension of primary silicon reduces from 70 mm to 20 mm and the average intercept length of eutectic silicon decreases to 2.1 mm by the optimum technique of P＋Sr compound modification. After the process of compound modification, tensile strength of Al-21Si-1.5Cu-0.5Mg-2.5Fe-1.5Ce alloy in room temperature can increase 21.5 % , which is identical with that of Al-21Si-1.5Cu-1.5Ni-2.5Fe-0.5Mg alloy under P＋Sr＋Ce compound modification.