Prediction Of Intermetallics Formation During Metal Ion Implantation Into Metal At Elevated Temperature

Considering the technical characteristics of metal ion implantation into metal Al, the prediction of intermetallics formation during metal ion implantation into metal at elevated temperature has been studied, based on the comparison with the experimental results. Because metal ion implantation into metal at elevated temperature possessed the characteristics of non-equilibrium interface reaction, the effective heat of formation model was built to predict intermetallics formation during metal ion implantation into metal at elevated temperature. The effective heat of formation was calculated by the heat of formation of the intermetallics that would form multiplying the ratio of the concentration of limiting element of effective concentration and the concentration of limiting element in the intermetallics. Among the different intermetallics in the metal-Al binary system, the intermetallics with the most negative effective heat of formation were predicted to form first. Adopting the effect heat of formation model to predict the intermetallics formed during metal ion implantation into metal Al, the lowest eutectic (liquidus) was chosen as the effective concentration in the metal-Al binary system. Compared with the experimental results of metal ion implantation into metal Al, the intermetallics Al13Fe4, HfAl3, MoAl12, NbAl3, NiAl3, TaAl3 and ZrAl3 were reasonably predicted to form during metal Fe, Hf, Mo, Nb, Ni, Ta and Zr ion implantation into metal Al by implanted energy of 50-140 keV, implanted dose of 1017~1018 ions cm-2, current density of 10-60 μA cm-2, at the implanted temperature of 300-600 ℃. Considering the formation of meta-stable phase, the effective heat of formation model predicted formation of the intermetallics Cr14Al86 at the temperature of 400 ℃, and Cr2Al13 at the temperature higher than 400 ℃. The intermetallics VAl3, V4Al23, VAl7 and VAl10 were predicted to form due to the precision of the thermodynamic data, taking the nucleation barrier at the solid-state interface into account, intermetallics VAl3 was predicted to form by the effective heat of formation model, and VAl3 was also the only intermetallics formed in the experiment. In view of the formationtemperature of intermetallics, the two phases MoAl12, MoAl5 and TiAl3, TiAl formed in metal Mo and Ti ion implantation into metal Al at the temperature higher than 600 ℃, respectively, where the effective heat of formation model was not valid in the condition.