Laser melt injection of ceramic particles in metals: processing, microstructure and properties

Abstract

The objective of this paper is to present an overview of the possibilities of the laser melt injection (LMI) methodology to enhance the surface of light-weighted metals by adding hard ceramic particles in the top layer, with the aim to enhance the wear resistance and to increase the hardness. In particular, the LMI process and the resulted microstructures are exemplified on two material systems, i.e., SiC particles in Al and WC particles in Ti-6Al-4V. The microstructural response on loading of both systems is studied by in situ deformation tests and the microstructure is analysed in detail by advanced microscopy techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM) and orientation imaging microscopy (OIM). It is shown that the LMI method is a suitable technique to create a MMC layers on metal substrates. The formation of reaction layers between the particles and the matrix may have a positive contribution on the bond strength between the particles and the matrix. However, the amount of reaction products in the matrix of the coatings should be minimised to improve the properties of the MMC layers.