Fundamental differences between spray forming and other semisolid processes

Abstract

The distinguished microstructural features of spray formed products are the refined equiaxed grain structure and lower segregation level. Attempts have been made in the past to propose mechanisms to explain the formation of equiaxed grain structure. Recently there has been a tendency in correlating spray forming with other semisolid processes such as liquid phase sintering (LPS) and rheocasting. In this article, the fundamental differences between spray forming and the other semisolid processes are discussed. Results show a unique thermal and solute profile on the deposit surface, resulting from the mixing of rapidly solidified metal formed during atomization and the solute-poor liquid formed by addition of the liquid of alloy composition, which contributes mainly to the microstructural evolution during spray forming. A simple experiment was designed to give supporting evidence to this view.