title: Dislocation Strengthening without Ductility Trade-off in Metastable Austenitic Steels.
abstract: Strength and ductility are mutually exclusive if they are manifested as consequence of the coupling between strengthening and toughening mechanisms. One notable example is dislocation strengthening in metals, which invariably leads to reduced ductility. However, this trend is averted in metastable austenitic steels. A one-step thermal mechanical treatment (TMT), i.e. hot rolling, can effectively enhance the yielding strength of the metastable austenitic steel from 322 ± 18 MPa to 675 ± 15 MPa, while retaining both the formability and hardenability. It is noted that no boundaries are introduced in the optimized TMT process and all strengthening effect originates from dislocations with inherited thermal stability. The success of this method relies on the decoupled strengthening and toughening mechanisms in metastable austenitic steels, in which yield strength is controlled by initial dislocation density while ductility is retained by the capability to nucleate new dislocations to carry plastic deformation. Especially, the simplicity in processing enables scaling and industrial applications to meet the challenging requirements of emissions reduction. On the other hand, the complexity in the underlying mechanism of dislocation strengthening in this case may shed light on a different route of material strengthening by stimulating dislocation activities, rather than impeding motion of dislocations.
authors.affiliation: State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, Xi'an 710049, China.|College of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Jiabin
authors.initials: J
authors.lastname: Liu
authors.affiliation: Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Jin
authors.affiliation: College of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Xiaoyang
authors.initials: X
authors.lastname: Fang
authors.affiliation: College of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Chenxu
authors.initials: C
authors.lastname: Chen
authors.affiliation: Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Feng
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Liu
authors.affiliation: Northwestern Polytechnical University, Xi'an, 710072, China.
authors.forename: Yuzeng
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Northwestern Polytechnical University, Xi'an, 710072, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Suo
authors.affiliation: Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Zhao
authors.affiliation: College of Materials Science and Engineering, Chongqing, 400044, China.
authors.forename: Tianlin
authors.initials: T
authors.lastname: Huang
authors.affiliation: Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Hongtao
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 China.
authors.forename: Xi
authors.initials: X
authors.lastname: Wang
authors.affiliation: College of Electrical Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Youtong
authors.initials: Y
authors.lastname: Fang
authors.affiliation: LNM, Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Wei
authors.affiliation: College of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Meng
authors.affiliation: Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Hong Kong, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Lu
authors.affiliation: Institute of Applied Mechanics, Zhejiang University, Hangzhou 310027, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Yang