Effect of anisotropy and strain rate sensitivity of lightweight alloys on power spinning

Anisotropy and rate dependence of mechanical properties are critical factors influencing the service performance of magnesium (Mg) alloy cone components. In this study, the anisotropy of AZ31 Mg alloy hot-rolled sheets was quantitatively measured using uniaxial compression tests. Moreover, the rate-dependent behavior was confirmed by testing at various strain rate ranges from 1×10-4s-1 to 1×10-1s-1. These anisotropic and rate-sensitive properties were incorporated into a finite element model of the power spinning process. Simulation results demonstrated that both anisotropy and strain rate sensitivity affect the formability of AZ31 Mg alloy. The anisotropy influences stress distribution in both radial and circumferential directions and causes variation in unfitability along the circumferential direction. Importantly, strain rate sensitivity becomes a dominant factor under high roller feed ratios. Therefore, accurate finite element modeling of AZ31 alloy power spinning must consider strain rate effects. These findings highlight the necessity of optimizing process parameters, particularly roller feed ratio and mandrel speed, to minimize stress and geometry inconsistencies, thereby mitigating the adverse effects of anisotropy and rate dependence.