The effect of Sr and Fe additions on the microstructure and mechanical properties of a direct squeeze cast Al-7Si-0.3Mg alloy
The effect of Sr and Fe additions on the microstructure and mechanical properties of a direct squeeze cast Al-7Si-0.3Mg alloy
复制标题
DOI：
10.1007/s11661-999-0283-6
复制
发表时间：
1999-05
期刊：
影响因子：
--
通讯作者：
J. Dong;P. Karnezis;G. Durrant;B. Cantor
中科院分区：
文献类型：
--
作者：
J. Dong;P. Karnezis;G. Durrant;B. Cantor
本文介绍了对重力压铸和直接挤压铸造 LM25 合金 (Al-7Si-0.3Mg-0.3Fe) 的微观结构和机械性能的研究结果。与重力压铸 LM25 合金相比，直接挤压铸造 LM25 合金具有优异的机械性能，特别是在延展性方面，在 T6 热处理条件下，延展性从重力压铸 LM25 合金的约 1.7% 增加到直接挤压铸造 LM25 合金的约 8.0%。延展性的增加是由于（1）孔隙率的去除，（2）Si颗粒尺寸的减小，以及（3）Fe-Si-铝化物颗粒的细化。直接挤压铸造中的高冷却速率导致Si颗粒的淬火改性，使得可能不需要用Sr或Na进行化学改性。此外，直接挤压铸造对合金中铁杂质的容忍度更高，因为它形成的铁硅铝化物颗粒比重力压铸材料中的颗粒更小。直接挤压铸造 LM25+Fe 合金 (Al-7Si-0.3Mg-1.0Fe) 的延展性约为 6.5%，而 T6 热处理条件下重力压铸 LM25+Fe 合金的延展性约为 0.5%。对铁杂质耐受性的提高可以导致制造成本大幅降低，因为（1）降低了原材料成本，（2）减少了模具粘着，以及（3）提高了模具寿命。
This article describes the results of an investigation into the microstructure and mechanical properties of a gravity die cast and direct squeeze cast LM25 alloy (Al-7Si-0.3Mg-0.3Fe). The direct squeeze cast LM25 alloy has superior mechanical properties compared to the gravity die cast LM25 alloy, especially with regard to ductility, which is increased from ∼1.7 pct for the gravity die cast LM25 alloy to ∼8.0 pct for the direct squeeze cast LM25 alloy in the T6 heat-treated condition. This increase in ductility is due to (1) the removal of porosity, (2) a decrease in Si particle size, and (3) a refinement of the Fe-Si-aluminide particles. High cooling rates in direct squeeze casting result in quench modification of the Si particles, such that chemical modification with Sr or Na may not be required. In addition, direct squeeze casting is more tolerant of Fe impurities in the alloy, due to the formation of smaller Fe-Si-aluminide particles than those in gravity die cast material. The direct squeeze cast LM25+Fe alloy (Al-7Si-0.3Mg-1.0Fe) has a ductility of ∼6.5 pct, compared to that of ∼0.5 pct for the gravity die cast LM25 + Fe alloy in the T6 heat-treated condition. This increase in tolerance to Fe impurities can lead to a substantial reduction in manufacturing costs due to (1) reduced raw-material costs, (2) reduced die sticking, and (3) improved die life.