CAJ | 학술논문

采用铸造方法制备不同Mg含量的过共晶Al?Si合金，并研究Mg含量对合金中初生Mg2Si显微组织的影响。结果表明：随着Mg含量的增大，Mg2Si的体积分数呈线性增加，但是平均晶粒尺寸没有呈线性增加。当Mg含量为3%时，Mg2Si晶粒的?100?晶向生长速度最快，Mg2Si易生长成八面体状。随着Mg含量的升高，晶粒固液界面溶质分布不均匀，合金形成不规则八面体结构。当Mg含量约为10%时，Mg2Si生长成尺寸较大的复杂结构。
채용주조방법제비불동Mg함량적과공정Al?Si합금，병연구Mg함량대합금중초생Mg2Si현미조직적영향。결과표명：수착Mg함량적증대，Mg2Si적체적분수정선성증가，단시평균정립척촌몰유정선성증가。당Mg함량위3%시，Mg2Si정립적?100?정향생장속도최쾌，Mg2Si역생장성팔면체상。수착Mg함량적승고，정립고액계면용질분포불균균，합금형성불규칙팔면체결구。당Mg함량약위10%시，Mg2Si생장성척촌교대적복잡결구。
Hypereutectic Al?Si alloy with variant Mg contents were fabricated by casting, and the effects of Mg content on the microstructure of primary Mg2Si particles in hypereutectic Al?Si alloys were investigated. The results show that the volume fraction of primary Mg2Si particles increases linearly with raising the Mg content, but the average size of Mg2Si particles does not exhibit a corresponding change. When the Mg content is 3%,?1 0 0?directions have the fastest growth velocity, so that Mg2Si particles are likely to form octahedron shape. When gradually increasing the Mg content, the distributions of Mg and Si atoms on the solid?liquid interface become inhomogeneous, which results in the formation of irregular octahedron structures. Finally, when the Mg content is about 10%, the morphology of primary Mg2Si particles changes from the octahedron shape into various complex structures with a large size.