The effects of special extrusion on the grain refinements of magnesium alloy

摘要

To research the effects of extrusion process and its process parameters on evolutions of microstructures for magnesium alloy, and the process includes initial extrusion and subsequent shearing process and is shorten for 'ES'. The simulation models have been built by using the DEFORM software. Temperature and strain evolution for deformation varying with initial billet temperatures has been explored. An experimental extrusion with installed container and ES die has been constructed. The maximum temperature rises in the billets are not increasing with billet temperature rise. The temperatures of rod surface increase continuously with development of ES extrusion. ES processes can improve microstructure refinement of AZ31 magnesium alloy. The simulation results and microstructure observation show that ES process can introduce compressive and accumulated shear strains into the magnesium alloy and improve the dynamic recrystallisation during ES extrusion. The research results show that ES is an efficient and inexpensive grain refinement method for magnesium alloys.