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选用SIMA法制备的LC4合金及液相线凝固法制备的LC9合金为原料 ,研究了半固态加工Al Zn Mg合金的组织演化。由于这两种方法制备半固态坯料的机理完全不同 ,因此这两种材料加工后的组织演化规律截然不同 :LC4合金的晶粒尺寸由于聚结而长大 ,而LC9合金的显微组织没有明显的变化。借助于扫描电镜和能谱分析 ,对半固态加工前后的显微组织进行成分分析 ,结果表明晶界处由共晶区、低熔点的富Cu区和杂质区三部分组成 ,且LC9合金的再加热组织的液相薄膜厚度大于LC4合金的 ;半固态加工后制件各部分的成分基本一致 ,证明半固态加工成形过程中材料的流动方式为层流
The microstructure evolution of semi-solid Al Zn Mg alloy was studied by using LC4 alloy prepared by SIMA method and LC9 alloy prepared by liquid-phase solidification method. Due to the completely different mechanism of preparation of semi-solid billet by these two methods, the microstructure evolution of these two materials is quite different after processing: the grain size of LC4 alloy grows due to coalescence and the microstructure of LC9 alloy is not obvious The change. The composition of the microstructure before and after the semi-solid machining was analyzed by SEM and EDS. The results show that the grain boundary consists of the eutectic zone, the Cu-rich zone with low melting point and the impurity zone. The LC9 alloy The thickness of the liquid film in the heated structure is larger than that of the LC4 alloy. The composition of the parts in the semi-solid processing is basically the same, which proves that the material flow in the process of semi-solid processing is laminar