Sr、B、Zr复合变质对Al-30Si组织和性能的影响

Effect of Composite Modifier on Microstructure and Mechanical Properties of Al-30Si

常规铸造的过共晶铝硅合金中初生硅粗大,共晶硅呈针片状,α塑性相不多。复合变质可以在一定程度上解决这些问题,但各类变质剂的变质效果不一。本文通过正交试验研究了Sr-B-Zr联合细化变质对Al-30Si合金的显微组织、硬度及抗拉强度的影响。结果表明,该联合变质剂能细化初生硅和共晶硅,使α相大量增多。影响合金抗拉强度的主要因素为Zr,最佳变质剂组合为0.06%Sr、0.03%B、0.06%Zr,合金抗拉强度可提高49.98%。影响合金硬度的主要因素为B,最佳变质剂组合为0.01%Sr、0.01%B、0.01%Zr,合金硬度可增加2倍。

Hypereutectic A1-Si alloy has thick primary Si, needle-like eutectic Si and few plastic phase a. Composite modifier can solve these problems to a certain extent ,but all kinds of modifiers have different effects. The effect of the Sr,B,Zr composite modifier on microstructure, tensile strength and hardness of A1-30Si were studied by orthogonal test .The results show that this modifier can refine primary silicon and eutectic silicon, leading ct particles increasing .The main effect factor for the tensile strength of alloy is Zr and the best modifying agent combination is 0.06% Sr0.03% B0.06% Zr .The tensile strength can raise 49.98%.B is the main factor for the effect of the alloy＇s hardness and the best combination of the modifier is 0.01%St,0.01%B,0.0 1%Zr .The hardness increases two times compared with A1-30Si without addition modifier.