Effect of graphite reinforcement on AA7050/B4C metal matrix composites

Abstract

Hybrid metal matrix composites with more than two particle reinforcement based on aluminium are extremely popular for use in heavy duty applications, and the quantity of these reinforcing particles may be adjusted to produce the necessary mechanical characteristics (strength and wear resistance). Due to the inferior tribological properties of AA7050 alloys often utilized in aircraft and vehicle applications, particle reinforcements are being added to enhance the matrix alloy characteristics. The primary aim of this research is to prepare the AA7050/B4C/Gr hybrid HMMC’s through the stir casting process with varying mass proportions of reinforcements. In this examination, AA7050 alloy is being used as the matrix material with graphite reinforcements ranging from 3 to 12 wt % in steps of 3% and keeping 9 wt% B4C constant. In this work mechanical properties like tensile strength and hardness were investigated. The composites hardness was decreased by 3.5% when reinforced with 9wt. % B4C and 3wt. % Gr in aluminium 7050 alloy. The composites tensile strength was decreased by 5.8% when reinforced with 9wt. % B4C and 3wt. % Gr in aluminium 7050 alloy. The investigation revealed that the incorporation of graphite particles in to the AA7050/B4C MMC’s decreased the mechanical properties like tensile strength and hardness in the composites. This is because of the graphite reinforced composites are soft in behavior and hence have a lower resistance to crack propagation and initiation. Scanning electron microscopy (SEM) analysis is used to investigate the micro structural properties of composites.