Synergetic Effects of Complex Additions of Mo and Ni on the Phase Transformation Behavior and Mechanical Properties of Austenitic Lightweight Steels

Fe–30Mn–10.5Al–1.1C alloys with different Mo and Ni contents are prepared to investigate the phase transformation behavior mechanical properties of austenitic lightweight steels. Solution-treated samples have microstructures consisting an austenite matrix ordered κ-carbides, size κ-carbides decreases addition or Ni. In addition, body-centered cubic (BCC) phases B2 DO3 also form when 3wt%Mo 3wt%Ni complexly added, resulting in a large decrease grain size. Nanoindentation experiments show that intrinsic strength changes depending on precipitation κ-carbide; i.e., by suppressing κ-carbide precipitation, while complex additions increase them again. The results tensile tests alloy containing both exhibits highest yield (1102 MPa) (1155 ductility (33%) due effects refinement grains formation secondary hard B2, as well κ-carbides. Finally, investigated via transmission electron microscopy atom probe tomography analyses.