Effect of elasto-plastic compatibility of grains on void-initiation criteria in low-carbon steel

Abstract

The present study evidences the role of ferrite grain size distributions on the occurrence of void initiation in a low carbon steel. Various thermomechanical treatments were done to create ultrafine, bimodal and coarse range of ferrite grain distributions. A two parameter characterization of probable void initiation sites is proposed; elastic modulus difference and difference in Schmid factor of the grains surrounding the void. All microstructures were categorized based on the ability to ease or resist void nucleation. For coarse grains, elastic modulus difference as well as the Schmid factor difference is highest, intermediate for ultrafine and lowest for bimodal microstructure.