Development of fine-grained structure caused by friction stir welding process of a ZK60A magnesium alloy

Abstract

A fine-grained microstructure average grain size of which is around 2 μm was developed in ZK60A magnesium alloy subjected to a FSW process. Material flow arose mainly from basal slips and was governed by simple shear deformations caused by the tool rotation. The development of the fine-grained structure was a complex process driven by severe plastic deformations, formation of deformation bands, grain splitting, twinning and dynamic and/or static recrystallizations. It appears also that the microstructural evolution depended on morphology of the dispersoids. © 2009 The Japan Institute of Metals.