Enhancing Microstructure and Mechanical Properties of AZ31-MWCNT Nanocomposites through Mechanical Alloying

T. H. Rao,J. Jayakumar,B. K. Raghunath

doi:10.1155/2013/539027

Abstract

Multiwall carbon nanotubes (MWCNTs) reinforced Mg alloy AZ31 nanocomposites were fabricated by mechanical alloying and powder metallurgy technique. The reinforcement material MWCNTs were blended in three weight fractions (0.33%, 0.66%, and 1%) with the matrix material AZ31 (Al-3%, zinc-1% rest Mg) and blended through mechanical alloying using a high energy planetary ball mill. Specimens of monolithic AZ31 and AZ31-MWCNT composites were fabricated through powder metallurgy technique. The microstructure, density, hardness, porosity, ductility, and tensile properties of monolithic AZ31 and AZ31-MWCNT nano composites were characterized and compared. The characterization reveals significant reduction in CNT (carbon nanoTube) agglomeration and enhancement in microstructure and mechanical properties due to mechanical alloying through ball milling.

Highlights

Mg alloy based MMCs among other MMCs are widely used in various applications in aerospace, automobiles, and sports equipments because of its low density and better mechanical properties [1]
Three weight fractions of Multiwall carbon nanotubes (MWCNTs) 0.33%, 0.66%, and 1% were added to the matrix of AZ31 and blended through high energy planetary ball mill to improve the homogeneity of the reinforcement material and to reduce the agglomeration as reported in the literature [12]
The reinforcement material MWCNT with three weight fractions of 0.33%, 0.66%, and 1% was added to the matrix of AZ31 alloy and blended through mechanical alloying using a high energy ball mill for 2 h at a speed of 300 RPM

Summary

Introduction

Mg alloy based MMCs (metal matrix composites) among other MMCs are widely used in various applications in aerospace, automobiles, and sports equipments because of its low density and better mechanical properties [1]. CNTs are discovered to have young’s modulus and tensile strength in the range of 3 TPa and 2 GPa, respectively, and density in the range of 2.0 g/cm3 [7, 8] Looking in to these properties CNTs could be an ideal reinforcement for Magnesium and its alloy as matrix material. Three weight fractions of MWCNTs 0.33%, 0.66%, and 1% were added to the matrix of AZ31 and blended through high energy planetary ball mill to improve the homogeneity of the reinforcement material and to reduce the agglomeration as reported in the literature [12]. Similar method was applied to fabricate the specimens of AZ31 without CNTs. The specimens of AZ31 and AZ31-CNT composites were characterized for the microstructure and mechanical properties and compared for the effect of increasing weight fraction of CNTs, mixing medium, cold compaction, sintering temperature, and hot extrusion

Experimental Details

Results and Discussion

Conclusions