Simultaneous enhancement of strength and ductility through coordination deformation and multi-stage transformation induced plasticity (TRIP) effect in heterogeneous metastable austenitic steel

Here we reported a heterogeneous structural austenitic steel with super combination of high strength and ductility, which consisted of nano/ultrafine grains and a proper amount of micro grains. The high strength originates from high back stress hardening which evolved during coordination deformation process between different domains. The huge variation in austenite grain size leads to obvious difference in austenite stability and consequently leads multi-stage transformation induced plasticity (TRIP) effect, which can enhance the strain hardening at different stages and sustain the plastic deformation to a large value.