Numerical Simulation of Microstructure of Al-Si/SiCp Composites during Stir Casting Process with Particle Pushing Model

Abstract

Particle distribution has vital influence on the microstructure and the final performance of particle reinforced metal matrix composite. The formation of microstructure of SiC particle reinforced Al-7.0mass%Si composite made by stir casting was simulated in this paper. Two-dimensional models under normal solidification condition including macro heat transfer, micro nucleation, equiaxed dendrite growth and particle pushing were presented. Two sets of meshes were used to carry out macro and micro calculation, respectively. A modified cellular automaton method coupled with finite difference method was used to simulate the evolution of the composite microstructure. In addition, the effects of SiC particle volume fraction, different casting processes, pouring temperature and cooling rate on the composite microstructure and the particles distribution were analyzed. The simulated results can clearly show the particle clustering/accumulation phenomenon caused by particle pushing. The calculated cooling curve and final predicted microstructure are in good agreement with the experimental results. Grain size is smaller for metal mould casting than sand mould casting. With the increase of SiC particle volume fraction or cooling rate, the grains of the matrix alloy are refined and particles are distributed more uniformly. As the pouring temperature increases, particles are distributed more uniformly.

Numerical simulation of the mold filling process of the brake lever for an electric multiple unit

“…This technique can predict the presence of any defects in the casting to screen better casting parameters, improve the casting quality, and realize cost savings. Li et al [6] used a SiC ceramic/Al-Si alloy composite as the research object and simulated the microstructure of the composite made by stir casting. The simulation results showed that particle clustering/ accumulation was caused by particle pushing, and the particles were distributed more uniformly as the pouring temperature increased.…”

Effect of the Stirring Velocity and the SiO2 Precursor Particles Feeding Rate on the Microstructure of the Al2O3/SiO2/Al Composites Prepared via Stir Casting Process

“…But it is difficult to measure the velocity distribution of molten aluminum under such a tough environment. Till date, with the help of computational simulation and numerical analysis method, several researchers [ 21–23 ] have paid attention on the quantification of particles clustering in the aluminum matrix composites under different fluid field parameters.…”