MACHINAB1L1TY STUDIES OF AI/SiC/B_4C METAL MATRIX HYBRID COMPOSITES USING PCD 1600 GRADE INSERT

摘要

Hybrid Metal Matrix Composites (MMC) (Al-SiC/B_4C) are widely used in aeronautical and automobile industries due to their excellent mechanical and physical properties. Due to the above properties these composites will slowly replace the conventional material application in aeronautical and automotive industries. However machining these composites is difficult because of the hard reinforcement of SiC and B4C particles. Wear is high which reduces the life of the tool. Conventional and coated tool materials lose their life within a short period of time. This paper presents the experimental investigation on turning A356 matrix metal reinforced with 10 % by weight of silicon carbide (SiC_p) particles and 5% by weight of boron carbide particles (the particle size of the silicon carbide and boron carbide ranges from 20 microns to 50 microns) fabricated in house by stir casting method. Fabricated samples are turned on medium duty lathe of 2kW spindle power with poly crystalline diamond (PCD) inserts of PCD grade 1600 at various cutting conditions. Parameters such as power consumed by main spindle, machined surface roughness, and tool wear and tear are studied. Scanning Electron Microscope (SEM) images support the result. It is evident that surface finish and power consumed are good for PCD grade 1600 at higher cutting speed also tool wear is strongly dependent on abrasive nature of hard reinforcement particles.