Investigation on improved micro-formability and forming mechanism under high strain rate of H62 brass in pulsed current-assisted laser impact micro-forming

Abstract

An innovative processing technology called pulsed current assisted-laser impact micro-forming was proposed to further improve the forming quality of microparts under a high strain rate. The experimental results showed that compared with the traditional annealing heat treatment, the pulsed current treatment significantly improved the formability of H62 brass under laser impact, and the enhancement amplitude increased with increasing pulsed current density. After the pulsed current treatment, the forming depth of the micro-parts under laser impact significantly improved, the necking phenomenon at the transition corner and the bottom of the microgroove was significantly alleviated, and the surface roughness of the micro-parts was effectively reduced. The microstructure of samples was also analyzed by transmission electron microscopy, electron backscattering diffraction, and other advanced characterization techniques. It was found that pulsed current pretreatment can further improve the micro-formability of materials under high strain rate by enhancing the inertial effect of materials, refining grains, and reducing the surface texture density evolution rate.