Strength - Ductility Balance of the Ultrafine-grained Ferrite and Cementite Structure

摘要

Grain refinement into 1#mu#m deteriorates the uniform elongation for steels, while it increases their yield strength remarkably. Thus, the concept of strain hardening design using hard second phases such as cementite particles was proposed to control the strength-ductility balance. moreover, we proved that restoration during annealing improves the uniform elongation of the ultrafine-grained ferrite steel through the heavy warm deformation. Based on these results, we studied the strength-uniform elongation balance of microstructures composed of ferrite and cementite that were fabricated by grooved warm rolling to show the ductile capability of the ultrafine-grained structure for steels.