Abstract：The formation energy and lattice constant of L12-structured Al3Zr, Al3Sc, Al3Yb, Al3(Sc0.5,Zr0.5), Al3(Yb0.5,Zr0.5) compounds were calculated from first-principles based on plane-wave pseudopotential method. The calculated results indicate that the L12-structured Al3(Yb0.5,Zr0.5) phase is thermodynamically stable and easy to precipitate coherently in Al matrix. With the results of TEM, high-density of coherent, L12-structured Al3(Yb,Zr) precipitates with 20-80 nm are precipitated in as-homogenized Al-Zr-Yb alloy, among them, core Zr-riched Al3(Yb,Zr) and core Yb-riched Al3(Yb,Zr) phases have obvious shell-core structure. Uniform and high density precipitation of L12-structured Al3(Yb,Zr) causes an improvement of precipitation-hardened effect and inhibit-recrystallization ability, compared to L12-structured Al3Zr precipitates in pure aluminum.
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2020, Vol. 25 
