Aging and recrystallization behavior of quaternary Al-0.25Zr-0.03Y-0.10Si alloy

Aging behavior of Al-0.25Zr-0.03Y-0.10Si were investigated to evaluate the role of 0.10%Si usually contained in commercially pure Al. Compared with the Si-free ternary alloy (Al-Zr-Y), accelerated aging kinetics, enhanced hardening effect and higher conductivity were obtained. Aging precipitates with tripled number density were observed in alloy Al-0.25Zr-0.03Y-0.10Si, whereas size and coarsening resistance were not affected by Si content, Contribution of Si provides a large number of nuclei, rather than accelerating the diffusion of Zr. Formation of primary Al3Y during solidification resulted in a 50 degrees C drop in recrystallization temperature.