Prediction of intermetallics formation during metal ion implantation into Al at elevated temperature

The model of effective heat of formation in metal-Al binary system proposed by Pretorius et al. was developed based on characteristics of the solid-state reaction at interface to predict the formation of intermetallics during metal ion implantation into Al substrate at elevated temperature. For the Fe, Hf, Mo, Nb, Ni, Ta and Zr ion implantation with the ion energy of 50-140 keV under the ion current density of 10-60 μA/cm2 into Al substrate to the implantation dose of 1017-1018 ions/cm2 at the elevated temperature ranging from 300 °C to 600 °C, the model of effective heat of formation predicted the formation of intermetallics Al13Fe4, HfAl3, MoAl12, NbAl3, NiAl3, TaAl3 and ZrAl3, which were consistent with the experimental results. Taking the kinetic factors and the limitation of thermodynamic data into account, the model of effective heat of formation explained the formation of metastable intermetallics Cr14Al86 at the lower temperature of 400 °C and of the stable intermetallics Cr2Al13 at the higher temperature of 510 °C, and the formation of simple intermetallics VAl3 relative to complex intermetallics V4Al23, VAl7, and VAl10, for the Cr and V ion implantation into Al substrate, respectively, at the elevated temperature up to 510 °C.