Effect of Sintering Temperature on the Properties of Aluminium-Aluminium Oxide Composite Materials

Abstract

In this study, aluminium-aluminium oxide (Al-Al2O3) metal matrix composites of different weight percentage reinforcements of aluminium oxide were processed at different sintering temperatures. In order to prepare these composite specimens, conventional powder metallurgy (PM) method was used. Three types specimens of different compositions such as 95%Al+5%Al2O3, 90%Al+10%Al2O3 and 85%Al+15%Al2O3 were prepared under 20 ton compaction load. Then, all the specimens were sintered in a furnace at two different temperatures 550 o C and 580 o C. In each sintering process, two different heating cycles were used. After the sintering process, it was observed that undistorted flat specimens were successfully prepared for all the compositions. The effects of sintering temperature and weight fraction of aluminium oxide particulates on the density, hardness and microstructure of Al-Al2O3 composites were observed. It was found that density and hardness of the composite specimens were significantly influenced by sintering temperature and percentage aluminium oxide reinforcement. Furthermore, optical microscopy revealed that almost uniform distribution of aluminium oxide reinforcement within the aluminium matrix was achieved.Keywords: Aluminium-Aluminium Oxide, Metal Matrix Composite, Density, Hardness, Microstructure 1. INTRODUCTION In recent years, particle reinforced metal matrix composites (MMCs) are gaining popularity for advanced applications. Generally, in processing of a metal matrix composite, a soft metal with high ductility and toughness is reinforced by a hard ceramic material with high strength and modulus. These metal-ceramic composites are capable of multiple functions in diverse engineering fields. For structural applications, aluminium based metal matrix composites have significant potential due to their high stiffness, modulus, specific strength, corrosion and wear resistance. In the development of these MMCs, substantial progress has been achieved so that these composites can be used for potential applications such as in automotive and aerospace industries. Researchers reported that these metal matrix composites are suitable for high performance structures and showed improved properties over conventional metals and alloys [1][2][3][4].Friction and wear behaviors of A359-20 vol% SiC particle composites slid against automobile friction material were experimentally investigated [5]. It was found that the wear resistance of the composites was greatly related to the strength and hardness of the SiC particles. Fatigue lives of aluminium alloy-alumina silicate particulate composites were investigated [6] and it was found that these composites showed longer fatigue lives in lower stress state than the unreinforced aluminium alloy whereas at elevated stress state, these composites exhibited reduced fatigue lives regardless of the reinforcement fractions. The properties of MMCs depend on many factors such as different properties of matrix material, size, shape, hardness, volume fraction and distribution of the re...

Ultrasonic Assisted Sintering Using Heat Converted from Mechanical Energy

“…In addition, the thickness of the aluminum oxide layer presented on the surface of original particles is about tens of nanometers [24], volume fraction can be estimated to be ~2%. Due to the short processing time, volume fraction changes little during UAS, therefore its effect on hardness is negligible [39]. In-depth explanation for the high hardness needs further symmetrical investigation.…”