An Enhanced Fe–28Mn–9Al–0.8C Lightweight Steel by Coprecipitation of Nanoscale Cu‐Rich and κ‐Carbide Particles

Abstract

Fe–Mn–Al–C austenitic matrix lightweight steels show a high ultimate tensile strength and total elongation but a relatively low yield strength. The yield strength is increased by coprecipitation of nanoscale Cu‐rich and κ‐carbide particles. For lightweight steel, strips of Fe–28Mn–9Al–0.8C (wt%) are prepared in near‐rapid solidification conditions, the addition of Cu up to 5 wt% leads to the coprecipitation of nanoscale Cu‐rich and κ‐carbide particles in certain heat‐treating conditions. The formation of Cu‐rich particles has promoted the precipitation of nanosized κ‐carbide particles. The yield strength of particle‐strengthened Fe–28Mn–9Al–0.8C–5Cu (wt%) austenitic matrix steel reaches 808 MPa with total elongation greater than 20%. Thus, the addition of 5 wt% Cu increases the yield strength of heat‐treated austenitic matrix lightweight steel without seriously deteriorating its plasticity by coprecipitation of nanoscale Cu‐rich and κ‐carbide particles.