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通过在铸造ＡｌＳｉ７Ｍｇ合金中加入一种新型复合变质剂，研究其对合金力学性能和组织的影响，并采用透射电子显微镜（ＴＥＭ）研究合金在时效过程中组织的变化。结果表明：采用此新型变质剂可有效提高铸造ＡｌＳｉ７Ｍｇ合金的力学性能。合金经５３５℃×６ｈ固溶化处理和１５０℃×６ｈ时效处理后，其σｂ达到３５１．７ＭＰａ，δ达７．７９％。经ＴＥＭ分析，采用此变质剂处理的铸造ＡｌＳｉ７Ｍｇ合金在时效过程中不仅会产生Ｍｇ２Ｓｉ相，而且发现了一种新的时效强化相。通过分析，认为该相的析出过程与Ｍｇ２Ｓｉ相似，且其析出温度要较Ｍｇ２Ｓｉ相略低。由于此新强化相的析出使得合金在较低温度时效时即可获得较好的强化效果，使合金在Ｔ５状态下即可获得高的综合力学性能
A new type of composite modifier was added into the cast AlSi7Mg alloy to study the mechanical properties and microstructure of the alloy. Transmission electron microscopy (TEM) was used to study the microstructure of the alloy during aging. The results show that using this new modifier can effectively improve the mechanical properties of AlSi7Mg alloy. After 535 ℃ × 6h solution treatment and 150 ℃ × 6h aging treatment, the σb reaches 351.7MPa and δ reaches 7.79%. TEM analysis shows that the AlSi7Mg alloy treated with this modifier not only produces Mg2Si phase during the aging process, but also finds a new aging strengthening phase. Through analysis, it is considered that the precipitation process of this phase is similar to that of Mg2Si, and its precipitation temperature is slightly lower than that of Mg2Si phase. Due to the precipitation of the newly strengthened phase, the alloy can obtain a better strengthening effect at a relatively low temperature and the alloy can obtain high comprehensive mechanical properties under the T5 state