Effects of Cryogenic Rolling on the Microstructure Evolution and Mechanical Properties of Low-Density Fe-28Mn-8Al-1C Steel

This study undertakes a systematic investigation into the influence of cryogenic rolling (CR) deformation on the microstructure evolution and mechanical properties of low-density Fe-28Mn-8Al-1C steel. The results reveal that the microstructure undergoes a series of transformations, from equiaxed austenite grains to elongated grains with strain bands, twinning, dislocation entanglements, and dislocation cells. The texture evolves from brass to copper with increasing deformation. Besides, the mechanical properties exhibit a direct correlation with the extent of deformation, as evidenced by the notable increase in ultimate tensile strength, yield strength, and microhardness from 882 to 1861, 505 to 1791 MPa, and 284 to 578 HV, respectively. However, elongation decreases from 64% to 6.6%, indicative of the strength-ductility trade-off. The aforementioned findings provide insight into the potential for manipulating the microstructure evolution and mechanical properties of low-density steels utilizing CR.