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

TL;DR

This study investigates how ferrite grain size distributions influence void initiation in low carbon steel, highlighting the roles of elastic modulus and Schmid factor differences in different microstructures.

Contribution

It introduces a two-parameter characterization of void initiation sites based on elastic modulus and Schmid factor differences in various ferrite microstructures.

Findings

Coarse grains show the highest elastic modulus and Schmid factor differences.

Ultrafine grains have intermediate differences, while bimodal microstructures show the lowest.

Microstructure influences the ease or resistance to void nucleation.

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.