Mg - Zinc - Y - Zr Alloy Flexible Angle Extrusion Numerical Simulation And Experimental Research

As one of the lightest structural material, magnesium alloy has been widelyapplied in many areas. However, because of the limit of its shortcomings such asthe low yield intensity, poor room temperature deformation capacity and so on,its application can’t compare with the traditional metal material like steel andaluminum. Wrought magnesium alloy has better performance compared totraditional cast magnesium alloy. Extrusion molding is an important means ofprocessing wrought magnesium alloy. In this paper, a new change channel. Inthis paper, a new variable channel angular extrusion (CCAE) way is applied,through the finite element analysis software Deform-3D numerical simulation ofchange channel angular extrusion of Mg-6Zn-1.2Y-0.6Zr alloy, analyzing theCCAE deformation behavior of materials, stress, and strain under differentextrusion temperature, extrusion speed and extrusion ratio. The experimentalmold was designed; Mg-6Zn-1.2Y-0.6Zr alloy CCAE experiment was verifiedunder extrusion ratio of2.25, extrusion speed0.8mm/s and extrusiontemperature from200℃to400℃. Evolution of the microstructure andmechanical properties were analyzed. The following results were obtained:1. The grid was refined at the extrusion corner and the changed channel.Improved extrusion temperature; the mesh became larger; the mesh becamesmaller when extrusion ratio and speed became larger.2. The main factors affecting the extruded product performance wereextrusion temperature, extrusion speed and extrusion ratio. The extrusiontemperature was higher, the pressing force was smaller; the extrusion ratio waslarger and extrusion temperature smaller, the pressing force was larger. Thedeformation was more intense, grain refinement was better equivalent and straindistribution was more uniform when extrusion force was larger.3. The average grain size was about5μm under the extrusion temperature of250℃of CCAE deformation. The grain size was small and evenly distributed.Grain size became large as the extrusion temperature increased. 4. Mechanical properties of the material were raised after the CCAEdeformation. Micro hardness, tensile strength, yield strength and elongationwere significantly improved. The tensile strength of material was288MPa at200℃and yield strength was210MPa at250℃, elongation was17.8at400°C. Tensile strength and yield strength decreased as extrusion temperatureincreased, but the elongation t elevated. The relationship between material yieldstrength and grain size is in line with the typical Hall-Petch relationship. Tensilefracture belonged to mixed fracture at low temperature (200℃-250℃)，at hightemperature(350℃-400℃) belonged to ductile fracture. The mechanicalproperties of extrusion product was relatively best at250℃。...