Friction Stir Processing Route for Metallic Matrix Composite Production

Abstract

The widely accepted casting routes to produce metal matrix composites (MMCs) present lot of challenges in the form of resultant material defects which include inhomogeneous reinforcement dispersion, deleterious interfacial reaction, porosity, and poor wettability. Friction stir processing (FSP) has become a popular method to produce bulk and surface MMCs. FSP was developed based on the working principles of friction stir welding. FSP overcomes the setbacks of casting routes. The physical and chemical properties of the reinforcement particles do not have significant effect on the process and the final dispersion in the matrix. FSP relies on severe plastic deformation and mechanical stirring action of the rotating tool to produce MMCs. It is possible to obtain homogenously dispersed particles with superior interfacial bonding between the matrix and the reinforcement at optimized processing conditions. The solid-state nature of the process avoids solidification related issues and alleviates possible interfacial reaction. This article presents an overview of the production of MMCs having different metallic matrices and reinforcements via FSP. The role of process parameters and tool design on the resulting microstructure and mechanical properties are also presented.