Numerical simulation of dendrite microstructure for Al-Si alloy with additive phase
有外加相存在时Al-Si合金枝晶微观组织的数值模拟

The interaction between spherical particles and dendrites,and the process of mi- crostructure formation including particle distribution for Al-7.0%Si(mass fraction)alloy with additive SiC particles were simulated.Based on heat and solute conservations,the solute redistribution,inter- face curvature and anisotropy were considered.Particle,solid,liquid as well as solid/liquid interface were treated respectively.The numerical models that describe the interaction between single parti- cle/multiple particles and dendrites were established.The engulfment/pushing phenomena between single particle and solidification interface were predicted,and solute concentration field and velocity field of the growing dendrites and solid/liquid interface shape close to particle were studied.The in- teraction process between multiple particles and dendrites,and the segregation of particles into the interdendrite regions were recurred.The simulated results show that the interaction between particles and advancing curved solid/liquid interfaces is non-steady state when the particle is pushed,while it can be treated as steady pushing mode when solidification velocity is lower than critical velocity.The simulated results of dendrite microstructure and particle distribution are in good agreement with the experimental ones.