Rare earth elements and transition elements are widely used in aluminum alloys, magnesium alloys and copper alloys due to their unique microalloying effects. With regard to in-depth research on the grain refinement characteristics of rare earth elements and transition elements, the combination of grain refinement and microalloying in the master alloys has a great impact on the theories and technical research of refinement, and the broadening of the application field of master alloys. This paper first summarizes the grain refinement mechanisms and analyzes the effects of rare earth elements and transition elements on the grain refinement of aluminum and aluminum alloys, and summarizes the elements suitable for the preparation of Al-M master alloys and their refinement mechanism.

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.