Austenite reversion and nano-precipitation during a compact two-step heat treatment of medium-Mn steel containing Cu and Ni

Breaking the strength-ductility paradox of very-low (≤0.05 wt.%)-C medium (3–12 wt.%)-Mn steels (MMnS) has been a hard-wired topic, since in these multi-step heat treatments are usually required to obtain austenite for improved ductility and precipitates higher strength. In this study, compact two-step treatment comprising short (2 min) annealing tempering was developed investigate synergetic effect reversion nano-precipitation on tensile behavior very-low-C MMnS containing 1.5 wt.% Cu Ni. The step promoted considerable amount reverted (33 vol.%), prevent Ni from partitioning into austenite, they were supposed maintain ferrite phase then promote subsequent stage. During step, nano-precipitates with concentration 20–50 at.% precipitation core enriched Cu, Ni, Al Mn observed phase. volume fraction reached 38.5 vol.% after tempering, which led ultimate strength 1222 MPa total elongation 29% by transformation induced plasticity during plastic deformation. current study demonstrates beneficial influence addition subsequently enables an enhanced strain hardening behavior, thereby improving mechanical property profile MMnS.