Studies on Mach Inability and Microstructures of Hypereutectic Al-Si Cast Alloys

Microstructure, mach inability and surface characteristics of hypereutectic Al-Si cast alloys are attempted in this study using refiners and modifiers. The objective of the present study is to findout a suitable insert and optimum levels of speed, feed and depth of cut for machining of treated and un-treated hypereutectic Al-Si cast alloys. The methodology involves melting of hypereutectic Al-Si alloys in a furnace and molten metal is degassed using a degassing agent before pouring operation. Mach inability tests were carried out using a lathe tool dynamometer using different turning inserts. Machining force is found to be reduced for coated inserts when compared to uncoated inserts. Results of treated alloys exhibit excellent surface finish, fine distribution of primary and secondary particles and reduced cutting forces com-pared to untreated cast alloys.