Production and high temperature wear characterization of AA 7075/Al2O3/Graphite hybrid nanocomposites by enhanced stir and ultrasound assisted casting method

Abstract

AA7075 based metal matrix composites are mainly focused on having improved mechanical and tribological properties at high temperature. Aluminium based hybrid nanocomposites have been fabricated through mechanical stirring and ultrasonic cavitation-assisted solidification process by reinforcing alumina and Graphite (Gr) nanoparticles. The three different materials have been studied for high-temperature environment tribological behaviour by taking the applied load, sliding velocity and temperature as process parameters. Design of experiment approach, namely Box-Behnken design, has been utilized for experiments. Results have been analyzed using ANOVA, and optimized parameters have been obtained using desirability approach to have better tribological characterization in AA7075 based hybrid nanocomposites. The AA7075(material-I) has more wear loss and coefficient of friction as compared to AA7075/3 wt% Al2O3/1 wt%Gr (material-II) and AA7075/1 wt% Al2O3/3 wt%Gr (material-III). It is observed that wear loss and coefficient of friction increases with increase in operating parameters. It is also exhibited that temperature has more effect as compared to other parameters on the wear loss and coefficient of friction. The material -II has low wear loss and coefficient as compared to other materials. As expected, the optimal operating condition for each of the material is found to be lower values of the operating range of each parameter used in current experimentation. The optimal temperature, load, and sliding speed are estimated for each of the three materials. At optimal operating conditions, the wear behaviour of material-II is much better as compared to material-I and material-III.