Li Chunmei, Cheng Nanpu, Chen Zhiqian, Xie Zhongjing, Hui Liangliang
Faculty of Materials and Energy, Southwest University, Chongqing 400715, China.
Materials (Basel). 2018 Apr 20;11(4):636. doi: 10.3390/ma11040636.
Al₃TM(TM = Ti, Zr, Hf, Sc) particles acting as effective grain refiners for Al alloys have been receiving extensive attention these days. In order to judge their nucleation behaviors, first-principles calculations are used to investigate their intermetallic and interfacial properties. Based on energy analysis, Al₃Zr and Al₃Sc are more suitable for use as grain refiners than the other two intermetallic compounds. Interfacial properties show that Al/Al₃TM(TM = Ti, Zr, Hf, Sc) interfaces in I-ter interfacial mode exhibit better interface wetting effects due to larger Griffith rupture work and a smaller interface energy. Among these, Al/Al₃Sc achieves the lowest interfacial energy, which shows that Sc atoms should get priority for occupying interfacial sites. Additionally, Sc-doped Al/Al₃(Zr, Sc) interfacial properties show that Sc can effectively improve the Al/Al₃(Zr, Sc) binding strength with the Al matrix. By combining the characteristics of interfaces with the properties of intermetallics, the core-shell structure with Al₃Zr-core or Al₃Zr(Sc1-1)-core encircled with an Sc-rich shell forms.
近年来，Al₃TM（TM = Ti、Zr、Hf、Sc）颗粒作为铝合金有效的晶粒细化剂受到了广泛关注。为了判断它们的形核行为，采用第一性原理计算来研究它们的金属间化合物和界面性质。基于能量分析，Al₃Zr和Al₃Sc比其他两种金属间化合物更适合用作晶粒细化剂。界面性质表明，处于I-ter界面模式的Al/Al₃TM（TM = Ti、Zr、Hf、Sc）界面由于具有更大的格里菲斯断裂功和更小的界面能而表现出更好的界面润湿效果。其中，Al/Al₃Sc具有最低的界面能，这表明Sc原子应优先占据界面位点。此外，Sc掺杂的Al/Al₃（Zr，Sc）界面性质表明，Sc能有效提高Al/Al₃（Zr，Sc）与Al基体的结合强度。通过结合界面特性和金属间化合物的性质，形成了以Al₃Zr为核或Al₃Zr（Sc1-1）为核、周围包裹富Sc壳层的核壳结构。
