Experiment Investigation And Numerical Simulation Of Plastic Forming For Mg₂B₂O₅/AZ63B Magnesium Matrix Composite

In this paper, Mg2B2O5w/AZ63B magnesium matrix composite was fabricatedby mechanical ultrasonic stirring casting using AZ63B magnesium alloy which iscommonly used in commercial applications as matrix and magnesium borate whiskerwith excellent performance and lower cost as reinforcement. Stress-relievingannealing, homogenization and pre-deformation process were performed respectivelyfor as-cast composites. The high temperature plastic forming performance ofMg2B2O5w/AZ63B magnesium matrix composite were investigated by means of hightemperature compression deformation and hot extrusion combining experiment andsimulation. The microstructures of Mg2B2O5w/AZ63B composite before and afterextrusion were investigated by means of optical microscope (OM) and scan electronmicroscope (SEM). The effect of deformation parameters on Mg2B2O5w/AZ63Bmagnesium matrix composite materials mechanics performance was investigatedusing hardness tester and SANS universal testing machine.The hot compression of as-cast, stress-relieving annealing and homogenizationtreatment Mg2B2O5w/AZ63B composites was studied at different temperatures(473-673K) and strain rates(5×10-5-0.5s-1) using Gleeble-1500D. The results showthat steady stress of Mg2B2O5w/AZ63B decreases with the increase of deformationtemperature and increases gradually with the increase of strain rate. The constitutivemodels of three state composites were calculated using true stress-strain data obtainedfrom high temperature compression test.The macroscopic simulation model of composites was established to simulatehot extrusion of as cast and heat treatment composites. Under different processparameters, extrusion experiments of as cast, heat treatment and pre-deformationcomposites were performed using extruder. The results show that the extrusionprocess simulation is consistent with experiment results.It exhibits typical banded structure characteristics that apiece microscopic areaswith different chemical composition of the composite were elongated after extruded.After hot extrusion deformation, brinell hardness of as-cast, stress-relieving annealing and homogenization treatment composites improve greatly, increase53.6%,56.4%and53.6%respectively. The ultimate tensile strength and elongation ultimate ofMg2B2O5w/AZ63B increase with the rise of temperature and increases with theincrease of the extrusion ratio. The mechanical properties of stress-relievingannealing and homogenization treatment composite materials are less affected byprocess parameters. The homogenization treatment composite have the most excellenttensile properties at room temperature.