Insight into the stacking fault energy, dislocation, and thermodynamic properties of L12-Al3X(X[dbnd]Sc, Ti, V) intermetallics from first-principles calculations

Abstract

The dislocation and thermodynamic properties of L12-Al3X(XSc, Ti, V) intermetallics were studied based on first-principles calculations. The computed stacking fault energies indicate the energy barrier for dislocation formation in Al3Sc is higher than that of Al3Ti and Al3V. Also, the negative anti-phase boundary(APB) energy for Al3V suggests the formation of APB is energetically favored, and this finding is further evidenced by electron localization function(ELF) and densities of states(DOS). Moreover, the computed Peierls energies and Peierls stress suggest the movement of edge dislocation is easier than screw dislocation in Al3Sc, Al3Ti, and Al3V. Further, the < 110 > (111) screw dislocation of Al3Sc and the < 110 > (111) edge dislocation of Al3V is the most difficult and easiest to move in all the studied systems, respectively. It is consistent with the computed ideal shear stress(τiss) for Al3Sc, Al3Ti, and Al3V. Moreover, we speculated the Al3Sc and Al3Ti in aluminum alloy may possess a better strengthening effect in comparison with Al3V. Finally, the thermodynamic properties of Al3Ti was found less dependent on temperatureare than that of Al3Sc and Al3V, the Al3Ti can serve as a better candidate for improving the heat resistance of aluminum alloys.