Justification of the Changes in Work Hardening Exponent Based on Micro-Mechanisms of Deformation in a Plain Carbon Steel

Abstract

Although several studies have been conducted on the evaluation of work hardening behavior of dual-phase steels with the Hollomon equation, few studies have investigated the factors affecting the number of work hardening stages and the changes of work hardening exponent. Therefore, the aim of this study is to provide a deeper understanding of the deformation micro-mechanisms affecting the work hardening exponent and work hardening behavior in terms of Hollomon equation. For this purpose, samples with microstructures of ferrite-cementite, ferrite-cementite-martensite and ferrite-martensite were produced using appropriate thermomechanical treatments and then subjected to tensile tests. The changes in the work hardening exponent of different microstructures were explained by using the results obtained from the microstructure based modeling of the deformation behavior of the samples. The rate of storage of dislocation loops around particles was suggested as the most important factor influencing the changes in work hardening exponent.

Keywords

• work hardening exponent
• deformation micro-mechanisms
• martensite
• cementite
• bimodal particle size distribution