Abstract
A novel variable temperature rolling (VTR) and annealing process was conducted on a metastable austenitic stainless steel. Strain softening occurred during tensile straining in both cold rolled and cryogenic rolled-annealed steels, leading to low uniform elongations of only 2-3%. In contrast, thanks to the metastable dual-phase heterogeneous lamellar structure achieved via the VTR process, a ultra-high strength of over 1 GPa was obtained, and strain hardening led to a remarkable increase of uniform elongation up to 10%. The high strength and ductility are attributed to the significant work-hardening derived from the superior heterogeneous deformation-induced hardening and sustained transformation-induced plasticity effect.
IMPACT STATEMENT
We identify a new variable temperature rolling and annealing process to achieve a metastable dual-phase heterogeneous lamellar structure, which overcomes strength-ductility trade-off by coupling of HDI hardening and TRIP effect.
Acknowledgments
This work was financially supported by the National Natural Science Foundation of China (grant number 52071066).
Disclosure statement
No potential conflict of interest was reported by the author(s).
Declaration of interest statement
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.