Tribological Properties of Micro and Nano TiO2 Reinforced Aluminium Metal Matrix Composites

Abstract

-Metal Matrix Composites (MMCs) have a prospective for improved wear resistance over the unreinforced alloy and are the most capable in achieving enhanced mechanical properties. In this research, composites of Al 6061-micro TiO 2 (5, 10 and 15 wt.%) and Al 6061-nano TiO 2 (0.5, 1.0 and 1.5 wt.%) were produced by stir casting technique. Hardness and wear tests were performed on the micro and nano composite specimens. The fabricated nano composites showed improvement in hardness and wear resistance over the micro composites. The microstructure of the worn out specimen was examined by scanning electron microscope. Considering all the factors, it can be concluded that aluminium based composite with 1.0% by weight nano TiO 2 reinforcement possess better wear resistance properties as compared to micro TiO 2 reinforced aluminium metal matrix composites. Keyword -Aluminium Metal Matrix Composites, wear resistance, stir casting, nano TiO 2., I. INTRODUCTION Metal matrix composites have a prospect for increased wear resistance over the unreinforced alloy and are the foremost promising in achieving increased mechanical properties [1]. Amongst different composites, MMCs are promising new materials for recent engineering applications having high specific strength, stiffness and their high temperature stability and widely used in aerospace and automotive industries. Aluminium is the most popular matrix for the MMC's and the aluminium alloys are quite attractive due to their low density, low cost, its capability to strengthen by precipitation, good corrosion resistance, high electrical and thermal conductivity and improved tribological properties [2,3]. The mechanical property results of micro and nano composites led in to improvement of wear rate, yield strength, ultimate tensile strength, compressive strength and hardness. The fabrication process such as compo casting and the size of the reinforcement particles were the effective factors influencing on the mechanical properties [4,5]. To avoid agglomeration of nano particles during solidification process, a non-contact method, where the ultrasonic probe is not in direct contact with the liquid metal was attempted to disperse nanosized Al 2 O 3 particulates in aluminium matrix and the mould was subjected to ultrasonic vibration [6]. SiC and Al 2 O 3 are the common reinforcing materials used in aluminum matrix composites [7].In recent times extensive study on Al-SiC composites has been made as SiC in particular delivers superior wear resistance and mechanical properties. Addition of SiC reinforcement to the base aluminum metal added strength to the composite [8]. The improvements in wear resistance of Al alloy-SiC particles reinforced composite is a strong function of reinforcement content and its size [9]. The occurrence of SiC makes the composites hard to be machined due to its brittle property. Adding up of metal oxides like TiO 2 shifts the brittleness of SiC and widens its engineering applications. Use of TiO 2 as reinforcement in aluminium alloy has established ...