摘要 : A comprehensive experimental and numerical investigation of TRIP effect on mechanical behaviors, strain partitioning and fracture is carried out on a low-alloyed TRIP steel with and without subzero treatment. Load responses of ind... 展开 A comprehensive experimental and numerical investigation of TRIP effect on mechanical behaviors, strain partitioning and fracture is carried out on a low-alloyed TRIP steel with and without subzero treatment. Load responses of individual phases and macroscopic mechanical properties are investigated through nanoinden-tation and uniaxial tensile tests. The increase of martensite volume fraction caused by subzero treatment improves tensile strength but appears detrimental to ductility. Two types of martensite transformation are observed: a twin-relationship variant selection to accommodate strain interior unstable austenite grains, and a variant selection based on the same crystal orientation as adjacent coarse ferrite grain reducing interfacial energy between ferrite and newly transformed martensite. A microstructure-based simulation model considering martensite transformation is developed with phenomenologically calibrated crystal plasticity parameters. The shift of strain localization from unstable austenite grain to neighboring ferrite grain is clarified to reduce the strain partitioning at interfaces. This effect is argued to be the origin of ductility enhancement in low-alloyed TRIP steel. 收起