Multi-scale Simulation Of ECAP Forming To AZ31Magnesium Alloy

AZ31magnesium alloy is the most widely used, however,magnesium alloy isclose-packed hexagonal crystal structure,plastic deformation of magnesiumalloy,deformation processing difficulties,which largely limits its application.Studies haveshown that grain refinement can be enhanced to plastic deformation,plastic deformation inorder to achieve alloys.For strain uniformity，and explore the evolution of microscopicgrains,for optimizing structure of AZ31magnesium alloy ECAP (Equal Channel AngularPressing, referred ECAP) die,and improving mechanical properties of magnesium alloys hasimportant practical significance.The help of numerical simulation technology, using the finite element method of macroand cellular automaton method(Cellular Automata,referred CA),combining in multi-scalesimulation to study ECAP extrusion process and microstructure evolution of grain structureof AZ31magnesium alloy,to optimizing ECAP extrusion die structure. on this basis，compared with the physical test，and further description of the strain uniformity ECAP diestructure parameters for optimizing the effectiveness and feasibility. This research is asfollows:1) Based on viscoplastic finite element method and CA method to simulate extrusionforming process of ECAP,dynamic reproduction of dynamic recrystallizationprocess,similar with previous existing research results, drawing that the most importantareas of grain refinement is a large plastic deformation zone at ECAP die structure.2) Experiments show that the microscopic grain refinement is reflected by macroscopicstrain uniformity, so to quickly design approach of ECAP die is gived on an uniform strain.3) by orthogonal experiments，either the strain distribution, but also reduce theextrusion force of the mold structure optimization parameters are gived(mold exterior angleof40°, angles of105°, angles radius of1.5mm).4) three key points typical on the blank are investigated microscopic grains evolutionof extrusion process, the results showed that: grain that it is not experienced in large plasticdeformation point (P1) of ECAP is growth,where the trend of dynamic recrystallization;P2point that starting position at ECAP extrusion large plastic deformation zone is undeergonesignificant dynamic recrystallization and grain refinement significantly; P3point that theend at ECAP extrusion large plastic deformation zone is followed by dynamicrecrystallization grain,thinning effect is not obvious.5) Large plastic deformation area isfrom inner corner to the outer corner of the mold，the grain refining effect gradually is weakened.6) through physical testing contrast，after ECAP deformation zone，a sample microstructure extrusion grain structure，compared with the original grain structure，phenomena of the grain refinement，which basically the same trend.