Effect of shape geometry on electromagnetic radiation under quasi-static compression in sintered aluminium preforms

Abstract

This paper presents the effect of shape geometry on electromagnetic radiation (EMR) emissions from sintered aluminium preforms during deformation under unrestricted quasi-static compression. The EMR emissions under compression show shape anisotropy. The end surface conditions of the compressing platens, i.e. lubrication, also influence the EMR emission characteristics. The first EMR emission invariably occurs near the yield. The dead metal zones formed on the top and bottom portions of the specimens during axial compression, possibly generate a climbing motion of edge dislocations in the radially outward mid-regions. These edge dislocations form accelerated electric line dipoles and emit electromagnetic radiation during the climbing motion. These results appear significant in understanding the mechanism of plastic deformation in metal powder preforms at the microscopic level and are expected to give a deeper insight into the metal forming processes.