Copper-precipitation hardening in a non-ferromagnetic face-centered cubic austenitic steel

Copper additions are utilized for precipitation hardening of a non-ferromagnetic austenitic face-centered cubic (fcc) steel. Additions of up to 25 wt.% Mn, 15 wt.% Ni, 6 wt.% Cu, and 0.6 wt.% C are found to stabilize austenite sufficiently to prevent transformation to either α′- or ε-martensite upon heavy mechanical deformation up to 75% reduction in thickness, with the alloys remaining paramagnetic. Mechanical properties are characterized and the tensile strength (447 MPa) is correlated with copper-precipitation as revealed directly by local-electrode atom-probe tomography.