Alloy Design of Al-Al3(Ti,V,Zr) Composite Systems through Phase Stability Calculations

Abstract

The knowledge of microstructures, hence properties can be found from an understanding of phase equilibria. Such an approach has been adopted in the present study to design Al-Al₃(Ti, V, Zr) composite system. Phase stabilities of multicomponent trialuminides are explored first by experiments at various temperatures and then thermodynamically optimized for the purpose of dispersing them in the rather soft aluminium matrix and eventually making composites. Using these obtained thermodynamic parameters, quasi-ternary Ti-V-Zr sections of Al-2at%(Ti, V, Zr) and Al-6at%(Ti, V, Zr) composite systems were calculated at 698K. At 698K, where aluminium alloys are put into service for high temperature use, phase diagrams, overall lattice misfits, volume fractions and coarsening rate constants were calculated. Based on these calculations, optimum alloy compositions which were supposed to maximize the strengthening effects at high temperatures were suggested.