Effect of Milling Time on the Microstructure, Physical and Mechanical Properties of Al-Al₂O₃ Nanocomposite Synthesized by Ball Milling and Powder Metallurgy.

Meysam Toozandehjani,Farhad Ostovan,Sidek Abdul Aziz,Khamirul Matori,Md Mamat

doi:10.3390/ma10111232

Meysam Toozandehjani, Farhad Ostovan + Show 3 more

Open Access

https://doi.org/10.3390/ma10111232

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Abstract

The effect of milling time on the morphology, microstructure, physical and mechanical properties of pure Al-5 wt % Al2O3 (Al-5Al2O3) has been investigated. Al-5Al2O3 nanocomposites were fabricated using ball milling in a powder metallurgy route. The increase in the milling time resulted in the homogenous dispersion of 5 wt % Al2O3 nanoparticles, the reduction of particle clustering, and the reduction of distances between the composite particles. The significant grain refining during milling was revealed which showed as a reduction of particle size resulting from longer milling time. X-Ray diffraction (XRD) analysis of the nanocomposite powders also showed that designated ball milling contributes to the crystalline refining and accumulation of internal stress due to induced severe plastic deformation of the particles. It can be argued that these morphological and microstructural variations of nanocomposite powders induced by designated ball milling time was found to contribute to an improvement in the density, densification, micro-hardness (HV), nano-hardness (HN), and Young’s modulus (E) of Al-5Al2O3 nanocomposites. HV, HN, and E values of nanocomposites were increased by ~48%, 46%, and 40%, after 12 h of milling, respectively.

Highlights

IntroductionDuring synthesizing Al-Al2 O3 nanocomposites, like other metal matrix composites (MMCs), achieving a uniform dispersion of Al2 O3 reinforcement particles and avoiding clustering of the Al2 O3 reinforcement particles, those at the nano-scale, would be a significant constraint
Upon milling of Al-5Al2O3 nanocomposite powders, aluminum particles are welded and fractured until reaching a steady state where equiaxed particles are formed in the presence of Al2 O3 nanoparticles
This study was conducted to investigate the effect of milling time on morphology, microstructure, and consequent physical and mechanical behaviour of pure Al-5Al2 O3

Summary

Introduction

During synthesizing Al-Al2 O3 nanocomposites, like other metal matrix composites (MMCs), achieving a uniform dispersion of Al2 O3 reinforcement particles and avoiding clustering of the Al2 O3 reinforcement particles, those at the nano-scale, would be a significant constraint. This is due to the fact that the enhancement of physical and mechanical properties is potentially decided by a uniform dispersion of Al2 O3 reinforcement particles within the matrix. Reinforcing the Materials 2017, 10, 1232; doi:10.3390/ma10111232 www.mdpi.com/journal/materials aluminum matrix, with Al2 O3 nanoparticles, necessitates a proper technique to obtain a uniform dispersion of Al2of

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