Phase diagram of the Al–Dy–Zr ternary system at 773 K

Abstract

Abstract X-ray powder diffractometry, scanning electron microscopy, optical microscopy and differential thermal analysis were used for constructing the isothermal section of the Al–Dy–Zr system in the whole compositional range at 773 K. The existence of 13 binary compounds and 1 ternary compound, i.e. Al3Zr, Al2Zr, Al3Zr2, AlZr, Al3Zr4, Al2Zr3, AlZr2, AlZr3, α - Al3Dy, Al2Dy, AlDy, Al2Dy3, AlDy2, and Al30Dy7Zr3 were confirmed. The ternary compound Al30Dy7Zr3 has AuCu3 structure (space group Pm3m) with lattice parameter of a = 0.4206 nm. The isothermal section consists of 17 single-phase regions, 32 binary-phase regions and 16 ternary-phase regions. The homogeneity of Dy in the binary compounds Al3Zr, Al2Zr, Al3Zr2, and AlZr2 is determined to be 2 at.%, 3 at.%, 4 at.%, and 2 at.% Dy, respectively. The homogeneity range of Dy in Zr is up to v7 at.% Zr. The solid solubility of Zr in the binary compounds Al3Dy, Al2Dy, and AlDy is determined to be 2 at.%, 26 at.%, and 3 at.% Zr, respectively.