Ensuring the strength and ductility synergy in an austenitic stainless steel: single- or multi-phase hetero-structures design

Heterogeneous microstructures have been proposed to optimize the mechanical properties in respect of strength and ductility synergy many alloy systems. In this work, multi-phase hetero-structured microstructure consisting fine grains coarse where ferrite is embedded vicinity nano-grains was obtained by regulating thermomechanical processing parameters. A yield 1.2 GPa which more than two times higher grained counterpart with less uniform elongation loss achieved steel. The microscopic load transfer complex investigated situ high energy synchrotron X-ray diffraction. persistent strain hardening ascribed hetero-deformation induced stress associated joint activation transformation-induced plasticity (TRIP) twinning-induced (TWIP) effects. As a comparison, single-phase steel exhibits little lower but ductility.