Production of al based composite reinforced with α-si3n4 and caracterization of its machinability properties

PRODUCTION OF Al BASED COMPOSITE REINFORCED WITH α-Si3N4AND CARACTERIZATION OF ITS MACHINABILITY PROPERTIES(M.Sc. Thesis)Ersin BAHÇECİGAZI UNIVERSITYINSTUTE OF SCIENCE AND TECHNOLOGYSeptember 2006ABSTRACTThe aims of this study, are to produce Al based composite reinforced withparticulate (MMCp) by powder metallurgy technique and to investigate itsmachinability properties. Al powders and 5, 10 and 15% weight ratios of α-Si3N4 particulates were mixed in an attritor for one hour. To produce transverserupture test and machinability test block samples, the mixed powders werecompacted at 800 MPa. Compacted block samples were sintered at 650 oC for 2hours in N2 atmosphere. Mechanical properties and microstructure of sinteredsamples have been investigated. Machinability tests were carried out by dryturning with PCD and K10 tools at different cutting speeds. Machinability hasbeen characterized with turning forces, surface roughness, chip types and chipformation. By increasing the percentage of Si3N4 weight ratio, transverserupture strength (TRS) decreased and the hardness of MMC samples increased.The highest TRS value was observed for the MMCp including 10% ceramicreinforcing materials. It was determined that the machined surface roughnessand turning forces of MMCp decreased with increasing α-Si3N4 ratio.During the machining of MMCp with PCD tool, minimum surface roughnessand minimum turning forces formed. Adhering tendency of Al matrix to theK10 tool caused excessive built-up edge formation and poor surface quality.Science Code : 710Key Words : Metal matrix composite (MMC), Powder metallurgy (P/M),Machinability, PCD, K10, Si3N4Page Number : 131Adviser : Assoc. Prof. Yusuf ÖZÇATALBAŞ