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本文采用受控凝固技术研究了 Al-Mg 合金的单向凝固特性,在不同的凝固条件下考察了稀土元素对合金的凝固特性、结晶方式、晶体组织及溶质元素枝晶偏析的影响。结果表明,稀土元素的加入增大了合金熔体的组成过冷倾向,使凝固过程中界面稳定性降低,促使结晶方式发生由平面至胞状及由胞状向胞状—树枝状的转变;当合金以枝晶方式凝固时,加入稀土元素使枝晶发达,枝晶间距减小,并在枝晶交汇处生成网络状三元共晶组织。化学成分的
In this paper, the controlled solidification technique was used to study the unidirectional solidification properties of Al-Mg alloys. The effects of rare earth elements on the solidification properties, crystallization methods, crystal structure and dendritic segregation of solute elements were investigated under different solidification conditions. The results showed that the addition of rare earth elements increased the overcooling tendency of the alloy melt and decreased the interfacial stability during the solidification process, which led to the transition from planar to cellular and from cellular to cellular to dendritic. When the dendrites are solidified, rare earth elements are added to dendrite and the dendrite spacing decreases, and the network-like ternary eutectic structure is formed at the dendrite junction. Chemical composition