Processing and deformation mechanisms of bulk ultrafine grained and nanostructured Mg alloy via mechanical alloying technique

Abstract

Processing, microstructures and mechanical properties of Mg alloys consolidated from mechanically alloyed powders at different milling durations have been investigated. At different milling durations, the dominant strengthening effect from grain size refinement, solid solution and particle strengthening were observed in the alloys. The strengthening of Mg alloy is associated with grain refinement, solid solution and particle dispersion at shorter milling durations. At longer milling durations, a decrease in yield stress together with strain softening behavior was observed. A yield stress of about 200 MPa with 45 % tensile elongation was found at room temperature for grain size of 45 nm. Strain rate tests and creep tests revealed a time dependent property present in the nano grained alloy. It is deduced that the deformation is mainly caused by grain boundary deformation process in the present work.