Effect of Dynamic Plastic Deformation and Subsequent Aging on the Microstructure and Mechanical Properties of an Fe–Mn–Al–Mo–C Lightweight Steel

Abstract

The microstructure and mechanical properties of an Fe–26Mn–8Al–1.2C–3Mo lightweight steel subjected to dynamic plastic deformation (DPD) at a strain of 0.3 or 0.5 and subsequent aging at 550 °C were investigated. The results show that DPD introduces a high density of dislocations and a significant grain refinement, leading to an increase of ~350–700 MPa in yield strength. Post‐DPD aging further increases strength because the strengthening from nanosized κ‐carbide precipitation and slight grain refinement outweighs the softening from partial dislocation recovery. Herein, Mo addition results in the formation of finer κ‐carbides and suppresses grain coarsening during aging. The sample subjected to DPD at a strain of 0.5 and aging at 550 °C exhibits outstanding mechanical properties, with a yield strength of ~1337 MPa, an ultimate tensile strength of ~1547 MPa, and a total elongation of ~26.4%.