Thermodynamic description of the Al–Fe–Zr system

Abstract

The Fe–Zr and Al–Fe–Zr systems were critically assessed by means of the CALPHAD technique. The solution phases, liquid, face-centered cubic, body-centered cubic and hexagonal close-packed, were described by the substitutional solution model. The compounds with homogeneity ranges, hex.- Fe 2Zr, Fe 2Zr, FeZr 2 and FeZr 3 in the Fe–Zr system, were described by the two-sublattice model in formulas such as hex.- Fe 2(Fe,Zr), (Fe,Zr) 2(Fe,Zr), (Fe,Zr)Zr 2 and (Fe,Zr)(Fe,Zr) 3 respectively. The compounds Al m Zr n except Al 2Zr in the Al–Zr system were treated as line compounds (Al,Fe) m Zr n in the Al–Fe–Zr system. The compounds FeZr 2 and FeZr 3 in the Fe–Zr system were treated as (Al,Fe,Zr)Zr 2 and (Al,Fe,Zr)(Fe,Zr) 3 in the Al–Fe–Zr system, respectively. All compounds in the Al–Fe system and hex.- Fe 2Zr in the Fe–Zr system have no solubilities of the third components Zr or Al, respectively, in the Al–Fe–Zr system. The ternary compounds λ 1 with C14 structure and λ 2 with C15 structure in the Al–Fe–Zr system were treated as λ 1 - (Al,Fe,Zr) 2(Fe,Zr) with Al 2Zr in the Al–Zr system and λ 2 - (Al,Fe,Zr) 2(Fe,Zr) with Fe 2Zr in the Fe–Zr system, respectively. And the ternary compounds τ 1 , τ 2 and τ 3 in the Al–Fe–Zr system were treated as (Al,Fe) 12Zr, Fe(Al,Zr) 2Zr 6 and Fe 7Al 67Zr 26, respectively. A set of self-consistent thermodynamic parameters of the Al–Fe–Zr system was obtained.