Performance Difference Between the Spoke and Rim in an Extruded AZ80 + 0.4%Ce Magnesium Alloy Wheel under Equal Strain

To tackle the critical challenge concerning the disparate performance outcomes between the spoke and rim in extruded AZ80 magnesium alloy wheel hub, finite element simulation was used to optimize the shape parameters of the hollow billet and improved equivalent strain was achieved. The paper studied the microstructure evolution and mechanical property response of the alloy after the forming process. The experimental results showed that the grain sizes of the spoke and rim were 32.95 and 33.84 μm, respectively, when using the optimized shape parameters, and both of them were completely dynamically recrystallized. Although the fine grain strengthening and precipitation hardening effects were consistently obtained in both samples, a discernible distinction was revealed by the mechanical property analysis. Specifically, the yield strength (YS) and ultimate tensile strength (UTS) of the rim specimens evinced a notable 13.8 and 15.4% higher in comparison to the spoke specimens. This discrepancy was further elucidated by the texture analysis, which illuminated that the spoke was distinguished by an extrusion direction–transverse direction double-peak basal texture, while the rim was marked by a normal direction–transverse direction (ND–TD) double-peak basal component after extrusion. The distinct texture patterns gave rise to varying predominant deformation mechanisms during loaded at room temperature, where the textured TD-oriented grains within the spoke unfriendly promoted the initiation of {10-12} tensile twinning at low yield stress, while both the ND and TD component within the hub manifested a markedly high activation of prismatic slip with high yield stress. The cumulative effect of these contrasting deformation pathways ultimately led to a marked contrast in the YS between the two regions.