Effect of composition and quenching cooling rate on the structure and morphology of Al-TM, Al-TM–REM alloys

The changes in the structural state of the base Al-3Zr wt% alloy depending on the casting temperature, quenching cooling rate, and the target alloying were studied. It was shown that low cooling rate of 10 1 deg/sec of the base alloy causes formation of two preferential size (about 10 and 2 µm) of dispersed particles that uniformly distributed in the Al-0.12Zr wt% matrix. Increasing cooling rate to 10 3 °/s causes rise of Zr content in the matrix from 0.12 to 2.4 wt%. Thus, in this case, a precondition of formation of nano-sized Al3Zr hardening particles is appeared. At the highest cooling rate (10 6 °/s), turbulent convection flows are formed, as well as a vortex structure with Al 3 Zr particles. The addition of 3–4% Mg to the base alloy increases the melt viscosity, suppresses thermal diffusion processes, levels the concentration on the free and contact side, and increases the degree of supersaturation of the solid solution. The use of Sc, Er micro-alloying completely eliminates the formation of large particles, and contributes to the refining of primary intermetallic compounds to d ~ 1 μm with a significant increase in their precipitation density.