Microstructure and Mechanical Properties of Al-Si Alloy Prepared by Spray Forming

Spray forming (SF) is a matter of special interest because of its simple process, low cost and the low oxygen content in products. In this experiment, three SF preforms were prepared of Al-Si alloy sprayed with various "gas to metal (G/M)" ratio. The microstructure and mechanical properties of the preforms and extruded materials were investigated, and found to be controlled by the G/M ratio. Increase of the G/M ratio reduces primary silicon size and hence lowers wear resistance. On the contrary, the strength of the extruded materials increases with increasing G /M ratio.