Effect of rate of deformation on electromagnetic radiation during quasi-static compression of sintered aluminium preforms

Abstract

Abstract This paper presents some experimental results on the intermittent electromagnetic radiation (EMR) characteristics of sintered aluminium powder preforms under quasi-static compression. The stress level within the gross elastic limit and yielding of the partially compact preforms at which first EMR emission is observed, bears a distinct parabolic relation with the rate of compressive deformation. These observations can be developed into a new technique to detect the compactness of sintered metal powder preforms for industrial components. Further, each successive intermittent EMR emission at all rates of deformation requires increasing incremental strain energy during progressive plastic deformation. The electromagnetic energy release rate decreases sharply as the rate of deformation is increased and then attains a more or less constant value at higher rates of deformation. These results appear significant in understanding the mechanism of plastic deformation in metal powder preforms at the microscopic level, not yet reported in the literature.