材料期刊网

A model was developed to describe the microstructure evolution in a hyper-monotectic alloy directionally solidified in a static magnetic field. Solidification experiments were carried out with Al-Pb alloys and the microstructure formation in the sample was calculated. The numerical results agree with the experimental ones well. They indicate that the magnetic field affects the microstructure formation mainly through the damping of the convections. It causes a more uniform distribution of the nucleation rate and the volume fraction of the minority phase droplets along the sample radial direction. It also causes a decrease in the maximum size of the minority phase droplets in front of the solidification interface. All these are favorable for the obtaining of a hyper-monotectic alloy with well dispersed microstructure. (C) 2009 Elsevier B.V. All rights reserved.