Deformation Driven Precipitation in Binary Magnesium Alloys

Unlike Aluminum (Al) alloys, precipitation strengthening of Magnesium (Mg) alloys has proven challenging. Precipitate density is typically too low, and precipitate size is often too large and elongated to enhance the resistance to plastic deformation significantly. Mimicking recent work in Al alloys, we are exploring how low-temperature plastic deformation can enhance the density, size, and morphology of common intermetallic particles and thereby lead to significant hardening in Mg alloys. The low temperatures tend to favor nucleation overgrowth, while the deformation provides vacancies and dislocations that can assist nucleation. Using equal channel angular extrusion, and moderate temperatures, we explore the processing and thermodynamic factors controlling nucleation and growth of precipitates in Mg-Al and Mg-Zn binary alloys.