Characterization of High-current Pulsed Electron Beam Interaction with AISI 1045 Steel and the Microstructure Evolution

Abstract

In this paper, the process of pulsed electron beam interaction with AISI 1045 steel is the main focus under investigation. The electron beam is generated by “pseudo-spark” discharge device and characterized by high current (hundreds of amperes to thousands of amperes), short pulse duration (hundreds of nanoseconds to thousands of nanoseconds), high frequency (hundreds of Hz to thousands of Hz) and self-focused beam diameter (typically 0.5-5mm), which are more favorable for metal surface treatment compared with the conventional thermal-emission electron beam diode. In this work, both the microstructure evolution of the metal target and the temporal evolution of the target surface plasma and vapor are investigated by a diversity of diagnostic methods. The influence of the plasma phase on the formation of surface irregularities are analyzed and discussed. The experimental setup is introduced, surface microstructure and chemical composition of AISI 1045 steel pre and post pseudo spark electron beam treatment are investigated by using scanning electron microscope (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS, also called EDX). The mechanisms of the metal surface profile evolution are proposed based on the experimental results. It is demonstrated that the pseudo-spark based electron beam parameters can be optimized to decrease the surface irregularities within the proper pulse irradiation time and plasma density range.