Effect of Aging and Cold Rolling on the Microstructure and Mechanical Properties of a New Fe-Mn-Al-Cr-C Duplex Alloy

The microstructural changes that occur during aging and cold rolling of a new Fe-Mn-Al-Cr-C duplex alloy have been investigated. Two treatments were developed to produce either a good combination of tensile strength and ductility (σu=800 MPa, σy=525 MPa, and A=46%) or a high strength (σu=1340 MPa, σy=1200 MPa, and A=15%) with a ductile type of fracture after aging at 320 °C. Aging between 550 °C and 700 °C led to a significant decrease in strength and ductility due to the precipitation of the brittle βMn phase. However, aging above 750 °C showed a considerable increase in strength and ductility due to the precipitation of very fine grains of ferrite within the austenite phase.