Formation of Mo(Si, Al)(2) layer on Mo dipped in Al melt saturated with Siand the effects of transition metals added in the melt

Dipping Mo into Al liquid with saturated Si, a dense Mo(Si, Al)(2) layer wa s formed on the Mo surface. Microstructure observation and chemical composi tion analysis of the Mo(Si, Al)(2) layer reveal that the intermetallic laye r consists of needle-like grains with diameter of submicrons and Al-Si liqu id at their grain boundaries. Mo(Si, Al)2 grains are grown by the dissoluti on-precipitation process in the Al(Si) liquid located between Mo(Si, Al)(2) and Mo. The product layers at the corners of Mo had radial cracks because the Mo(Si, Al)(2) layer generated at the interface between the Mo(Si, Al)2 layer and Mo. Addition of Cr into the Al-Si liquid bath can prevent the for mation of radial cracks. (C) 2001 Elsevier Science Ltd. All rights reserved .