Effects of Ce-Rich Mischmetal on Microstructure Evolution and Mechanical Properties of 5182 Aluminum Alloy

This paper addresses the effects of Ce-rich mischmetal on the microstructure evolution of a 5182 aluminum alloy during annealing and rolling processes. The Ce-rich mischmetal was added to an as-cast 5182 aluminum alloy in an induction furnace, and this was followed by homogenized annealing at 450 °C for 24 h and a rolling operation. The microstructure evolution and mechanical properties' analysis of the 5182 Al alloy were characterized. The results show that the Ce-rich mischmetal could modify the microstructure, refine the α-Al grains, break the network distribution of Mg₂Si phases, and prevent Cr and Si atoms from diffusing into the Al₆(Mn, Fe) phase in the as-cast 5182 Al alloys. Ce-rich mischmetal elements were also found to refine the Al₆(Mn, Fe) phase after cold rolling. Then, the refined Al₆(Mn, Fe) particles inhibited the growth of recrystallization grains to refine them from 10.01 to 7.18 μm after cold rolling. Consequently, the tensile strength of the cold-rolled 5182 Al alloy increased from 414.65 to 454.34 MPa through cell-size strengthening, dislocation density strengthening, and particle strengthening. The tensile strength of the recrystallization annealed 5182 Al alloy was increased from 322.16 to 342.73 MPa through grain refinement strengthening, and this alloy was more stable after the recrystallization annealing temperature.