基于正交试验对铸造铝合金电导率和抗拉强度影响规律的分析

挑选了铝合金中常用的9种合金元素，根据这些元素对铝合金物理性能和微观组织的影响规律和影响机制进行了分类。通过设计四因素三变量正交试验分析了这些合金元素对Al-7Si合金导电性能和抗拉强度的影响规律，为开发兼具高导电(热)性能和高强度铸造铝合金提供了有价值的工艺参考。通过对比发现，Sr元素能有效将共晶Si相变质为纤维状，这有利于合金电导率的提升；质量分数为0.6%的Fe也能适当提升合金的电导率。Sb元素能有效将共晶Si相变质为细小片状，这有利于合金抗拉强度的提升；质量分数为0.5%的Ni或0.5%的Zn也能适当提升合金的抗拉强度。Sr和Sb同时加入合金中，共晶Si相的变质效果会恶化，并导致粗大片状共晶Si相析出。

Analysis of influencing rules on conductivity and tensile strength of cast Al alloys based on orthogonal experiment

Nine commonly used alloying elements in Al alloys were selected and classified according to their influence rules and mechanisms on the physical properties and microstructure of Al alloys. The influence rules of these alloying elements on the electrical conductivity and tensile strength of Al-7Si alloy was analyzed by designing four factor and three variable orthogonal experiments, which provided a valuable process reference for the development of cast Al-Si alloys with excellent electrical (thermal) properties and high strength. Through comparison, it is found that Sr element can effectively modify the eutectic Si phase into fibrous, which is conducive to the improvement of the conductivity of the alloy; 0.6% mass fraction of Fe can also appropriately improve the conductivity of the alloy. Sb element can effectively modify eutectic Si phase into fine flakes, which is conducive to the improvement of tensile strength of the alloy; 0.5% mass fraction of Ni or 0.5% mass fraction of Zn can also appropriately improve the tensile strength of the alloy. When Sr and Sb are added to the alloy at the same time, the modification effect of eutectic Si phase will deteriorate, resulting in the precipitation of coarse flake eutectic Si phase.