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采用分子动力学方法研究了纯Fe材料中嵌入固相Fe纳米团簇后的凝固过程。结果表明,嵌入的纳米团簇能够显著降低过冷度,凝固得到的Fe的结构为γ-Fe。当凝固发生时,嵌入的Fe纳米团簇能够保持其形状。凝固过程首先从纳米团簇与Fe液的界面处开始发生,其形核长大阶段会交替出现稳定的FCC层和亚稳的FCP层。随后在结构弛豫阶段,大部分亚稳态FCP结构会逐渐转变成稳态的FCC结构。嵌入纳米团簇的结构能决定Fe液在凝固过程中的晶格取向和结构演化以及凝固的最终结构。
The solidification process of pure Fe material embedded in solid Fe nanoclusters was studied by molecular dynamics method. The results show that the intercalated nanoclusters can significantly reduce the undercooling and the structure of the solidified Fe is γ-Fe. When coagulation occurs, the embedded Fe nanoclusters can retain their shape. The solidification process starts from the interface between the nanoclusters and the Fe liquid, and the stable FCC layer and the metastable FCP layer alternately appear during the nucleation and growth phase. Subsequent structural relaxation phase, most of the metastable FCP structure will be gradually transformed into a steady state FCC structure. The structure of embedded nanoclusters can determine the lattice orientation and structure evolution of Fe solution during solidification and the final structure of solidification.