A Study on the Precipitates in Rapidly Quenched Al-Ti-Zr Alloys

Two kinds of Al-Ti-Zr alloys were prepared to investigate the coarsening of the spherical L12-structured Al3(Ti, Zr) precipitates aging at 425℃for various periods of time. The results indicated that the increasing of Zr-content would result in increasing the coarsening rate of the precipitates. The coarsening coefficients of Ll2 structured Al3(Ti0.25Zr0.75) and A13(Ti0.75Zr0.25) precipitates in these Al-5vol.%Al3(Ti. Zr) alloys are 3.94×10^(-28) and 1.61×10^(-28) m^3/hr, respectively. The hardness data shows that the peakaging of both two alloys were aging at 425℃ for 100 hours, and the peakaging hardness of Al-0.65Ti-3.22Zr and Al-1.74Ti-1.14Zr alloys were HV 75 and HV 78, respectively.