MACHINING CHARACTERISTICS OF Al505 HYBRID COMPOSITES FABRICATED BY STIR CASTING PROCESS

Abstract: Aluminium hybrid metal matrix composites are gaining their usage in aerospace, automotive industries because of their inherent properties like high strength to weight ratio, low wear rate, etc. Aluminium 5052 metal matrix composites reinforced with Aluminium oxide (Al2O3) and Graphite (Gr) were fabricated by using stir casting process. Stir casting is selected because of its simplicity, flexibility, applicability to large quantity production and cost economic. The samples were fabricated by keeping the matrix and reinforcement percentages constant as Al5052 (94%), Al2O3 (4%) and Gr (2%). The samples were then tested for its machining characteristics. Drilling was carried out on the fabricated samples by varying the Spindle speed, feed rate and Drill bit material. Three process parameters and three levels were considered and Taguchi L9 orthogonal array design of experiment was taken. The output parameters such as Material Removal Rate (MRR) and Surface Roughness (SR) were measured for the drilled samples. The optimal process parameter of Spindle speed 1000 rpm, feed rate 150 m/min and Drill bit material HSS - TiAlN coated was obtained for maximum material removal rate of value 0.466 g/sec. The optimal process parameter of speed 3000 rpm, feed rate 150 m/min and Drill bit material HSS - TiN Coated was obtained for minimum surface roughness of value 1.182 microns.

Keywords: Stir casting, matrix, reinforcement, Material Removal Rate and Surface Roughness.