Study on Refining Grain and Microalloying Effect of Al–5Er Master Alloy

The effects of the size of the primary phase and its dispersion on the refinement and microalloying effect of Al–5Er master alloy were studied by refining experiment, microhardness, SEM, XRD and TEM. The results show that the primary phase Al3Er can produce grain refining effect when the additive amount of Er in Al–5Er master alloy is 0.1 wt %. After plastic deformation, the size of primary phase is reduced, the dispersion of primary phase is more uniform, and the refining effect is further improved. After ARB three times, the refining effect is the best and the grain size of α-Al is 850 μm. After direct aging treatment, the hardness of the pure aluminium sample did not change. After solution and aging treatment, the hardness of the sample reached the peak in 15 min of aging, and the increase rate of microhardness reached 51%, which was attributed to the precipitation of nanoparticle Al3Er.