A study on properties of aluminium matrix hybrid composites

Abstract

Aluminium composites (AA7075) have been extensively used in automotive and aerospace industry. In the present research work, aluminium and graphite based hybrid nanocomposites have been fabricated by using two techniques, namely, mechanical stirring and ultrasonic cavitation-assisted solidification process. The alumina (Al2O3) and Graphite (Gr) nanoparticles were used as reinforcements in the developed hybrid nanocomposites. The fabricated hybrid nanocomposites were characterized using optical microscope, X-ray diffractometer and Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS). These image analysis techniques helped in ensuring that the reinforcement particles have been uniformly distributed. The process parameters such as weight percentage of alumina, weight percentage of graphite and mechanical stirring time may have considerable effect on various mechanical properties like Hardness, Toughness and Compressive Strength of composites. Hence selection of appropriate composition and process parameters is important. Same has been investigated in this research work. newlineThe study is divided in three phases. Phase I deals with investigation of mechanical behaviour. Phase II deals with high temperature tribological properties. Phase III focuses on Mathematical/Numerical Analysis of hybrid nanocomposites to exhibit mechanical properties and to identify their applications. Finally, economic analysis was carried out to estimate per unit cost of the composite fabricated. newlineDuring phase I: The experiments were planned and executed as per Box-Behnken design of experiments approach (seventeen experiments). newlineA number of hybrid nanocomposites were fabricated by varying weight percentage of alumina (1 to 3%), weight percentage of graphite (1 to 3%) and stirring time (5 to 15 minutes). The die temperature (400 and#730;C) and ultrasonic stirring time (15 min.) were taken as fixed. newlineThe major finding of phase I is that the mechanical properties improved due to combined effect of mechanical and ultrasonic