Published online by Cambridge University Press: 03 March 2011
The microstructure of gas-atomized Al-20 wt. % Si-1 wt. % Ni powders was investigated by electron microscopy. Primary Si crystals about 2 μm in size are homogeneously distributed in the Al matrix. Eutectic Si crystals about 50 nm in size are precipitated with the definite crystallographic relationship of 〈110〉Si ‖ 〈110〉Al. Most of the interfaces between Al and Si are semicoherently bonded with close-packed planes of {111}Si and {111}Al. The special crystallographic relationship and interfaces are interpreted by matching between Si and Al lattice spacings.