Abstract
To explore the deformation mechanisms of a new composite extrusion including extrusion and successive shear subsequently which is shorten ES, Three dimensional finite element modeling of grain refinements for magnesium alloys by ES process has been researched. The ES die have been designed and manufactured and installed to the horizontal extruder. Finite element software DEFORMTM-3D to investigate the plastic deformation behaviors of magnesium alloy during extrusion-shear has been employed. The extrusion loads and temperatures distribution of billets and maximum extrusion forces have been obtained from simulation results. From the simulation results it is clear that evolutions of extrusion loads curve and effective stresses and temperatures can be divided into three stages. ES process has been applied to fabricate AZ31 magnesium alloy rod at preheat temperature of 420oC with extrusion speed of 20 mm/s. The results proved that the ES process is a formality method for magnesium suitable for large scale industrial application. The microstructures of AZ31 magnesium alloy along the longitudinal section of rods have been sampled and examined and observed. Fine grained microstructures can be observed throughout longitudinal section of extruded rod. The researches results show that ES process would cause severe plastic deformation and improve the dynamic recrystallization of AZ31 magnesium alloy. The simulation results and calculated Zener-Hollomon parameters showed that the grains of magnesium would be refined gradually during ES process.
Highlights
Magnesium (Mg) alloys have been used in transportation, communications, electronics and aerospace etc., and have become the focus concerned by all the countries in the world[1,2]
The values for maximum extrusion forces were obtained from the finite element simulation results
At the initial stage of the extrusions process, the billet was subjected to severe plastic deformation if billet contact with die corners
Summary
Magnesium (Mg) alloys have been used in transportation, communications, electronics and aerospace etc., and have become the focus concerned by all the countries in the world[1,2]. Its specific strength and rigidity are superior to iron and aluminum. The greatest limitation for the usage of wrought magnesium is its poor formability at room temperature. Because of its hexagonal closed packed (HCP) crystal structure and only two independent basal slip systems can be activated[3,4]. More than 90% of the Mg alloys currently are applied in cast state. In the future development of Mg alloys will rely on large scale production applications of wrought Mg alloy products. Deformation capacity and strength for the traditional extruded rods of Mg alloy is rather poor[5,6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
