Effect of Nanoscale Mesoscopic Structural States Associated with Lattice Curvature on the Mechanical Behavior of Fe-Cr-Mn Austenitic Steel

Abstract

The paper explores the effect of high-temperature cross rolling followed by cold rolling on the internal structure of metastable Fe-Cr-Mn austenitic stainless steel, formation of nonequilibrium martensite ε and α′ phases in it, dynamic rotations on fracture surfaces, fatigue life under alternating bending, and wear resistance. Scratch testing revealed a strong increase in the damping effect in the formed hierarchical mesoscopic substructure that promotes the formation of a nanocrystalline grain structure, formation of hcp ε martensite and bcc α′ martensite in grains, formation of a vortical filamentary substructure on the fracture surface, and an increase in the high-cycle fatigue properties and wear resistance. These processes are associated with a high density of nanoscale mesoscopic structural states that arise in lattice curvature zones during high-temperature cross rolling followed by cold rolling with smooth rolls. The described effects are explained by the self-consistent mechanical behavior of hcp ε martensite laths in fcc austenite grains and bcc α′ martensite laths formed in cold rolling of the steel after high-temperature cross rolling.