Morphology of ductile metals eroded by a jet of spherical particles impinging at normal incidence

Abstract

A detailed morphological study of the erosion of two metals (an aluminum alloy and copper) by normal impact of spherical glass erodent particles was conducted. Currently there is no universally accepted theory which describes erosion observations at normal impact. In this study damage patterns were studied at several stages of erosion. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used and surface profile measurements were made. Transformations induced by the erosion process were also studied and the dynamics of the erosion are discussed. The morphology of the damage pattern is a manifestation of the flow pattern of erodent particles and it provides insight into possible mechanisms active at different stages of erosion. The simultaneous appearance of both radial tracks as well as concentric rings is believed to be reported here for the first time. Wave crests are observed which contain an accumulation of metallic flakes. These flakes are also observed in all regions of the tested specimens during all phases of erosion. From morphological comparisons of the pits over a wide variation in driving gas pressure and time, a well-defined damage and erosion process is evident and preliminary analysis is advanced to explain the formation of the various damage patterns.