Thermodynamic description of the Al–Fe–Zr system

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.- Fe2Zr, Fe2Zr, FeZr2 and FeZr3 in the Fe–Zr system, were described by the two-sublattice model in formulas such as hex.- Fe2(Fe,Zr), (Fe,Zr)2(Fe,Zr), (Fe,Zr)Zr2 and (Fe,Zr)(Fe,Zr)3 respectively. The compounds AlmZrn except Al2Zr in the Al–Zr system were treated as line compounds (Al,Fe)mZrn in the Al–Fe–Zr system. The compounds FeZr2 and FeZr3 in the Fe–Zr system were treated as (Al,Fe,Zr)Zr2 and (Al,Fe,Zr)(Fe,Zr)3 in the Al–Fe–Zr system, respectively. All compounds in the Al–Fe system and hex.- Fe2Zr 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 λ1 with C14 structure and λ2 with C15 structure in the Al–Fe–Zr system were treated as λ1- (Al,Fe,Zr)2(Fe,Zr) with Al2Zr in the Al–Zr system and λ2- (Al,Fe,Zr)2(Fe,Zr) with Fe2Zr in the Fe–Zr system, respectively. And the ternary compounds τ1, τ2 and τ3 in the Al–Fe–Zr system were treated as (Al,Fe)12Zr, Fe(Al,Zr)2Zr6 and Fe7Al67Zr26, respectively. A set of self-consistent thermodynamic parameters of the Al–Fe–Zr system was obtained.