Development of Thin Walled A-356 Components by New Rheocasting Semi-Solid Metal Processing Technology (NRC)

Abstract

Rheocasting refers to a process in which a liquid metal is vigorously agitated during initial stage of solidification to produce globular semisolid slurry which remains highly fluid. This slurry is directly fed into any shaping operation to obtain SSM parts. Rheocasting is an energy saving as well as cost saving, good surface finish and negligible porosity for a specialized casting, in which heating step of thixocasting is completely eliminated. Rheocasting also offers shot size flexibility and amenable for processing of wrought alloys and metal matrix composites, which are otherwise difficult to process by thixocasting route. A slurry with globular shape of the solid phase particles and hence injected directly into the die. In the present development, Al base thin wall components for electronic packaging applications were produced by rheocasting process. The paper presents the die designing aspects, optimization of rheocasting process parameters to achieve the sound casting and mechanical property. Thin walled Al-Alloy components lot was realized by the novel processing technology, meeting dimensional accuracy, desired microstructure, mechanical property, value for high integrity component needed for space applications.