Effect of surface modification in aluminium alloy on mechanical and tribological properties using friction stir processing

Abstract

Abstract:- One of the important design parameters is weight saving constituents in structural applications. Aluminium and its alloys are the most attractive materials for structural components in automotive and aerospace applications because of their light weight and moderate mechanical properties. Aluminium alloys specifically the 1100 grade are used majorly in the manufacturing industries. However, this alloy exhibit poor wear resistance, which in turn causes reduction in the service life of components. One of the basic and effective method to enhance the wear resistance of Al alloys is through surface modification. Friction stir processing (FSP) is one of the effective method to modify the surface by grain refinement. Also FSP is used to fabricate the surface composite of the AA1100 with suitable reinforcement particle. In the present study, the tungsten carbide (WC) particles are reinforced into AA1100 substrate through FSP using two different tool geometries (i.e., cylindrical tapered and pentagon shaped), varying the number of passes over 3 levels of severity (i.e., 1, 3, and 6) and with different cooling rate , with constant tool rotational speed of 1200 rpm and traverse speed of 30 mm/min. The results show that the tool geometry, the number of passes and cooling rates affects the distribution of reinforcing particles, which in turn influence the composite characteristics like grain size distribution, hardness, tensile properties and wear resistance. FSP process has several advantages as it is a solid-state process, and also environment-friendly and energy-efficient. Based on the results it is identified that pentagon tool geometry is the most suitable tool geometry to fabricate Al/WC surface composite, with the best particle distribution is obtained from 6- passes with water cooling setup. The results are discussed based on the microstructure examination, mechanical property evaluation and fertting wear analysis.