Crater-formation-induced metastable structure in an AISI D2 steel treated with a pulsed electron beam

A detailed investigation concerning the microstructure and phase formations in the crater-erupted areas formed under low energy high current pulsed electron beam bombardment has been carried out for a treated AISI D2 steel. The crater formations are initiated at carbides. Such carbide eruption events change the composition, phase selection and grain growth behaviour inside the craters. Under these extremely non-equilibrium conditions, amorphous patches and feathery type structures containing twinned nano-grains are retained.