Abstract: A method of making an essentially void-free, cast silicon and aluminum product wherein silicon and aluminum components in solid form are placed in a receptacle, heated to completely melt the components and thoroughly and uniformly disperse the aluminum component within the silicon component, and cooling the mixture in a non-uniform manner whereby solidification of the mixture gradually progresses from one extremity of the mixture to another extremity thereof. The aluminum component does not exceed about 6% by weight of the total weight of the components in the receptacle. During solidification of the mixture, gases are vented therefrom through that portion of the mixture which is in a molten state.