The effect of grain boundary energy on the amorphous forming composition range of Zr–Fe–Al ternary system

• A method for AFCR prediction of ternary system has been proposed.
• The ΔG of Zr–Fe–Al has been calculated with the different grain sizes.
• The results suggest that the alloys with higher Fe–Zr content have higher AFA.

Mechanical alloying (MA), as one of the main methods of solid state amorphization (SSA), has been intensively used to prepare amorphous alloys. The composition of alloys and processing conditions of MA is very sensitive for the amorphous forming ability (AFA) or/and amorphous forming composition range (AFCR). During the MA processing, the powder was severely plastically deformed and broken into tiny grains with sub-micro or even nano scale size. In this work, a method for AFCR prediction of ternary system has been proposed based on a thermodynamic point of view and including the size-dependent grain boundary energy. The Gibbs free energy (ΔG) of Zr–Fe–Al system has been calculated with the different grain sizes. Compared with the experimental data, the present calculations are reasonable. The present calculations indicate that the smaller the grain size, the wider AFCR for Zr–Fe–Al system is. The present results also indicate that the higher Fe–Zr content alloys have higher AFA, and grain refinement benefits on extending the AFCR.