Manufacturing of nano-micro composites using friction stir processing

Abstract EN

Aluminum and its alloys are used extensively in aerospace and automotive industries because of its low density and high strength to weight ratio.

however, a poor resistance to wear and erosion is of serious concern for prolonged use.

metal matrix composites are most promising new class of materials that exhibit good wear and erosion resistance properties, higher stiffness and hardness at a lower density as compared to the matrix.

this is due to the presence of NANO and micro-sized reinforcement particles into the matrix.

aluminum matrix composites (AMCS) reinforced with particles and whiskers are widely used for high performance applications such as in automotive, military, aerospace and electricity industries because of their improved physical and mechanical properties in the composites relatively soft alloy like aluminum can be made highly resistant by introducing predominantly hard but brittle particles such as Al2O3.

hard particles such as Al2O3, SIC], TIC, TiO2, Cr2O3, or mixture of them, and others are commonly used as reinforcement in the composites.

the application of Al2o3 particle reinforced aluminum alloy matrix composites in the automotive and aircraft industries is gradually increasing for pistons, cylinder heads, connecting rods etc.

where the tribological properties of the materials are very important.

however, the presence of the ceramic particles in the metallic matrix result in higher strength and hardness, often at the expense of some ductility which makes the matrix brittle.

in this regard, it may however be noted that wear is a surface dependent degradation mode, which may be improved by a suitable modification of surface microstructure and / or composition.

hence, instead of bulk reinforcement, if the ceramic particles would be added to the surface, it could improve the wear and erosion resistance without sacrificing the bulk properties.

the enhancement of mechanical properties in the novel NANO-particle reinforced MMCS has been reviewed recently.

dispersion of the NANO-reinforcements particles on metallic substrate surface and the control of its distribution in a uniform manner is a critical and difficult to achieve by conventional surface treatments