title: Nanoscale origins of the damage tolerance of the high-entropy alloy CrMnFeCoNi.
abstract: Damage tolerance can be an elusive characteristic of structural materials requiring both high strength and ductility, properties that are often mutually exclusive. High-entropy alloys are of interest in this regard. Specifically, the single-phase CrMnFeCoNi alloy displays tensile strength levels of ∼ 1 GPa, excellent ductility (∼ 60-70%) and exceptional fracture toughness (KJIc>200 MPa√m). Here through the use of in situ straining in an aberration-corrected transmission electron microscope, we report on the salient atomistic to micro-scale mechanisms underlying the origin of these properties. We identify a synergy of multiple deformation mechanisms, rarely achieved in metallic alloys, which generates high strength, work hardening and ductility, including the easy motion of Shockley partials, their interactions to form stacking-fault parallelepipeds, and arrest at planar slip bands of undissociated dislocations. We further show that crack propagation is impeded by twinned, nanoscale bridges that form between the near-tip crack faces and delay fracture by shielding the crack tip.
authors.affiliation: Department of Materials Science &Engineering, Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China.
authors.forename: ZiJiao
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Materials Science &Engineering, Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China.
authors.forename: M M
authors.initials: MM
authors.lastname: Mao
authors.affiliation: Department of Mechanical Engineering &Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
authors.forename: Jiangwei
authors.initials: J
authors.lastname: Wang
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Bernd
authors.initials: B
authors.lastname: Gludovatz
authors.affiliation: Department of Materials Science &Engineering, Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Materials Science &Engineering, Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China.|Department of Mechanical Engineering &Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
authors.forename: Scott X
authors.initials: SX
authors.lastname: Mao
authors.affiliation: Institute for Materials, Ruhr University, 44801 Bochum, Germany.
authors.forename: Easo P
authors.initials: EP
authors.lastname: George
authors.affiliation: Department of Materials Science &Engineering, Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Yu
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Materials Science &Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Robert O
authors.initials: RO
authors.lastname: Ritchie