Effect of ball milling the hybrid reinforcements on the microstructure and mechanical properties of Mg-(Ti plus n-Al2O3) composites

JOURNAL OF ALLOYS AND COMPOUNDS

卷:509

Article

Sankaranarayanan, S.¹  Jayalakshmi, S.¹  Gupta, M.¹ 

[1] Natl Univ Singapore, Dept Mech Engn, Singapore 117576, Singapore

关键词: Metal matrix composites;    Mechanical alloying;    Rapid solidification;    Microstructure;    Mechanical properties;    Scanning electron microscopy (SEM);   

DOI  :  10.1016/j.jallcom.2011.04.083

来源: Elsevier

【 摘 要 】

In this study, composites containing pure magnesium and hybrid reinforcements (5.6 wt.% titanium (Ti) particulates and 2.5 wt.% nanoscale alumina (n-Al2O3) particles) were synthesized using the disintegrated melt deposition technique followed by hot extrusion. The hybrid reinforcement addition into the Mg matrix was carried out in two ways: (i) by direct addition of the reinforcements into the Mg-matrix, Mg-(5.6Ti + 2.5n-Al2O3) and (ii) by pre-synthesizing the composite reinforcement by ball milling and its subsequent addition into the Mg-matrix, Mg-(5.6Ti + 2.5n-Al2O3) BM. Microstructural characterization revealed significant grain refinement due to reinforcement addition. The evaluation of mechanical properties indicated a significant improvement in microhardness, tensile and compressive properties of the composites when compared to monolithic magnesium. For the Mg-(5.6Ti + 2.5n-Al2O3) composite, wherein the reinforcements were directly added into the matrix, the improvement in strength properties occurred at the expense of ductility. For the Mg-(5.6Ti + 2.5n-Al2O3) BM composites with pre-synthesized ball-milled reinforcements, the increase in strength properties was accompanied by an increase/retention of ductility. The observed difference in behaviour of the composites is primarily attributed to the morphology and distribution of the reinforcements obtained due to the ball-milling process, thereby resulting in composites with enhanced toughness. (C) 2011 Elsevier B. V. All rights reserved.

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