Effect of reinforcement and volume fraction on mechanical behaviour of AA7075/B4C/Fly-ash MMCp

Abstract

In this study, an effort has been made to develop a substitute material for automobile, aerospace and defence components with an aim to increase mechanical properties. Development of new material involves synthesis of Aluminium composite by the use of Stir casting method using AA7075 as matrix with B4C and Fly ash as particle reinforcement with the varying volume fraction of the reinforcement (2 - 6 wt.%) B4C and (2 wt. %) fly ash. Investigation of Mechanical properties such as hardness, tensile strength and impact strength have been done. SEM analysis of the composites was performed to observe the interfacial bonding between matrix alloy and the reinforcement and the distribution of the reinforcement in the matrix, and type of failure taking place during the tensile test. X ray diffraction of the alloy and the composite was also done to identify the major peaks of the phases present in the material. Results show significant improvement due to the addition of reinforcement in the hardness and tensile strength of the composite as compared to Al 7075 alloy whereas the impact strength has slightly decreased. Microstructural analysis of the composite shows that proper distribution of reinforcement particles in the matrix and the interface bonding was good. XRD analysis reveals the presence of MgZn2 precipitates in the solid solution of aluminium as an interfacial reaction.