Assessment of mechanically mixed layer developed during high temperature erosion of cermets

Cermets and hard metals are the materials of interest in applications where wear resistance is important. The examination of worn surfaces of these materials with scanning electron microscope had revealed the presence of mechanically mixed layer (MML). The chromium, titanium and tungsten carbide based cermets were selected for the current study. Materials were subjected to erosion testing under different impact angles and velocities. Silica particles were used as abrasive. Scanning electron microscope was used for microstructural studies. Micrographs of eroded surfaces allowed examining the mechanisms of material removal. The distribution of hardness and indentation modulus of subsurface layers was obtained through the Universal hardness indentation technique. It was found that the depth (or thickness) of the mechanically mixed layer and its structure is different for different cermet grades. The key stages of MML formation were observed and presented. Effect of impact angle and abrasive particles velocity on MML formation is outlined. MML properties are discussed in detail.