Intermetallic Growth and Interfacial Properties of the Grain Refiners in Al Alloys

Al(3)TM(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, Al(3)Zr and Al(3)Sc are more suitable for use as grain refiners than the other two intermetallic compounds. Interfacial properties show that Al/Al(3)TM(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/Al(3)Sc achieves the lowest interfacial energy, which shows that Sc atoms should get priority for occupying interfacial sites. Additionally, Sc-doped Al/Al(3)(Zr, Sc) interfacial properties show that Sc can effectively improve the Al/Al(3)(Zr, Sc) binding strength with the Al matrix. By combining the characteristics of interfaces with the properties of intermetallics, the core-shell structure with Al(3)Zr-core or Al(3)Zr(Sc1-1)-core encircled with an Sc-rich shell forms.