Development of Aluminium Based Mango Seed Mangiferaindica Shell Ash (MSSA) Particulate Metal Matrix Composite

Abstract

A composite material is a combination of two or more chemically distinct and insoluble phases; its properties and structural performance are superior to those of the constituents acting independently. MMCs are made by dispersing a reinforcing material into a metal matrix to improve their properties. They are prepared by powder metallurgy and casting, although several technical challenges exist with casting technology. Achieving a homogeneous distribution of reinforcement within the matrix is one such challenge, and this affects directly on the properties and quality of composite. In this work a composite is developed by adding Mango seed shell Ash (MSSA) particulate in Al- Si-Mg Alloy by mass ratio 5%, 10%, 15% and 20%.  The composite was prepared by stir casting technique. It is proposed to use this material for production of motorcycle wheel hub which are subjected to continuous wear as the hubs are in direct contact with the brakes and rotating sprockets. The MSSA, was characterized using X- ray fluorescent (XRF). The result reveals SiO_2, has the highest percentage composition followed by CaO, Al₂O_3, Fe₂O₃ and Mg₂O as major phases. The presents of these hard constituent compounds suggests that the mango seed shell ash can be used as particulate reinforcement in various metal matrices since the chemical composition has similarity with the XRF analysis of Periwinkle shell ash, rice husk, fly ash, and bagasse ash currently used in metal matrix composite. Mechanical tests such as hardness test and impact test were conducted. The results revealed that increase in the percentage of MSSA progressively increased the hardness of the material from 5% wt to a maximum hardness of 43.2 HV at 15% addition of MSSA. This represents a 26.16% improvement over the unreinforced alloy. However, the impact energy progressively decreases of the material from 5%wt of MSSA and later increased to optimum energy at 15% addition of MSSA. From the results it is concluded that composite material such as Al- Si-Mg/ MSSA is one of the options as a material for production of motorcycle hub. The wear test of the composite was then carried out using Taguchi design to optimize the range of MSSA from 5% wt -15% wt., Sliding speed of 5cm/s -20cm/s, sliding distance from 50m to 200m, and the load of 2N, 4N, 6N, & 8N respectively. Analysis of the result of SN ratio for wear rate shows the optimum wear resistant value is in the combination of Load=4N, sliding speed = 10cm/s sliding distance=200m and MSSA=15 wt% These also correspond with the analysis of wear maps & wear rate presented in the diagrams of dynamic friction coefficient (COF) for Al-Si- Mg/ MSSA Composite.