A TEM study of the microstructure of SiCp/Al composite prepared by pressureless infiltration method

A transmission electron microscopy study has been performed on the microstr ucture of SiC particulate reinforced Al-Si-Mg-Zn composite prepared by pres sureless infiltration method. It was found that the SiC particulates were c oated with reaction layers, which were composed of nanocrystalline MgAl2O4 spinel particles. The SiCP/MgAl2O4 interface was clean and free of secondar y phases. Moreover, Si phase was found to be either an additional layer on the spinel coating or isolated particles around the spinels, while a small amount of coarse Mg2Si phase was identified in the eutectics with Al grains . A thermodynamic analysis was used to assist the understanding of the phas e formations in the experimental materials. (C) 2001 Acta Materialia Inc. P ublished by Elsevier Science Ltd. All rights reserved.