Numerical simulation of rheoforming of Al2Y/AZ91 magnesium matrix composites

Based on the previous study of the rheological properties of Al2Y/AZ91 magnesium matrix composites, putting the Al2Y/AZ91 magnesium matrix composites apparent viscosity model into the simulation software, the liquid and semi-solid filling and solidification process of Al2Y/AZ91 magnesium matrix composites were simulated by simulation software. The pressure field, velocity field, solid distribution of solidification process and defects of forming process were analyzed. As the results showed, during the liquid filling process the distribution of pressure was inordinate, the melt flow was turbulent, and eddy current phenomenon was easy to produce in the mold cavity, due to the inconsistency of the internal cooling rate of the casting during the solidification process; the subsequent solidified eddy zone could not be filled effectively by metal liquid, and shrinkage cavity and porosity were produced during the solidification process. During the semi-solid filling process, the pressure transfer was relatively stable, the melt flow was laminar flow, velocity distribution was uniform, no eddy current phenomenon occurred, the solidification velocity of inside of casting had little difference from the solidification velocity of outside of casting, and no shrinkage cavity and porosity occurred during the solidification process. In order to verify the correctness of the simulation results, the rheological forming experiment was carried out. As the results showed, a large number of spherical grains were distributed in the microstructure of the rheological forming casting, and the casting quality was better with no cavity defect. The experimental results were in accordance with the simulation results. © Editorial Office of Chinese Journal of Rare Metals. All right reserved.