Studies on Properties of Micro-Nano ZrO2 Particulate Metal Matrix Composites

Abstract

A metal matrix composite (MMC) is a composite material with at least two constituent parts, one being a metal matrix and other is reinforcement. When at least three materials are present, it is called a hybrid composite. Aluminium is widely used in aerospace and automobile industries due to its low density and good mechanical properties, better corrosion resistance and wear, low thermal coefficient of expansion as compared to conventional metals and alloys. The aim involved in designing MMC materials is to combine the desirable attributes of metals and ceramics. This project is aimed at development of MMC having aluminium metal matrix with micro-nano particulate zirconium oxide reinforcement. Here aluminium (LM25) has been selected as base metal along with 12% ZrO2 (micro), 12% ZrO2 (nano) and 12% ZrO2 (6% micro + 6% nano) have been taken as reinforcements to produce MMC. The composite has been produced by liquid metallurgy technique (stir casting). The properties of chosen composite are compared with base metal for tension, wear, hardness, density and microstructure analysis. For the combination of Al-LM25 with 12% zirconium oxide (6% micro + 6% nano) the tensile strength (TS) and hardness had increased when compared to that of base metal and are between that of the micro and nano reinforced composite. The density of MMC cast is almost relevant to theoretical densities. For MMC, the wear rate increases for an increase in the speed for a given constant load and time. The microstructure study reveals that Al-LM25 and zirconium oxide have been distributed uniformly throughout the casting with less porosity.