High Strain Rate Superplasticity of Mg Based Composites Fabricated by Friction Stir Processing

Abstract

The nano-sized SiO₂ particles were added into the AZ61 Mg alloys via friction stir processing (FSP) to a volume fraction of 5–10%. After four FSP passes, the 10% composites had uniform dispersion of particles and grain size of 0.8 μm. This composite exhibited high strain rate superplasticity, with a maximum ductility of 470% at 1×10⁻² s⁻¹ and 300°C or 454% at 3×10⁻¹ s⁻¹ and 400°C while maintaining fine grains less than 2 μm in size.