Synthesis evaluation of mechanical properties machinability and tribological behaviour of AL WC Gr hybrid composites

Abstract

Aluminum alloys are increasingly used industrially for production of automobile components due to their good strength, stiffness, wear résistance, thermal stability, corrosion resistance and their light weight quality compared to other materials. Composite materials are replacing monolithic materials because of their ability to provide suitable combination of properties through proper selection of reinforcement. Al alloys are popularly used as matrix material for metal matrix composites. AMCs provide better machinability as well as good wear and thermal characteristics. AMCs reinforced with hard particles such as Al2O3, B4C, SiCp, WC and soft particles such as graphite and molybdenum disulphide enhance high strength, hardness and improve wear and frictional characteristics. Several researchers have conducted investigations on AMCs and reported that the size and weight percentage of the reinforcement primarily influences the hardness of the newlinecomposites followed by other factors. In the present study, AlSi7Mg alloy was chosen as the matrix and reinforced with varying proportions of WC and constant graphite (Both lt 1 microns) composites were fabricated through stir casting method. Graphite was used to provide the lubrication effect through the formation of lubricant film. WC is one of the reinforcements having the hardest high melting point. Three different composites (in wt %) Al/3WC/3Gr, Al/6WC/3Gr, Al/9WC/3Gr with a constant 3% graphite were prepared along with unreinforced alloy samples for comparison purposes. Design of Experiments (DOE) based on Taguchi method was employed to study the effect of process parameters on machinability, wear rate and Coefficient of Friction (COF) both at room and high temperatures. Multiple linear regression analysis were carried out, models were developed for machinability and wear parameters. newline newline