SSM casting was selected for each of these applications for different reasons - high integrity, pressure tightness and design simplification. In each case SSM processing provides several unique advantages over other candidates
The process capitalises on thixotropy, a physical state wherein a solid material behaves like a fluid when a shear force is applied. The SSM process requires a nondendritic feedstock that can be produced by applying mechanical or electromechanical stirring during alloy solidification at a controlled rate, or from fine-grained materials produced by powder metallurgy or spray forming methods. This feedstock, usually in billet form, is then heated to a temperature between its solidus and liquidus and formed in dies to make near-net-shape parts.
