TY - JOUR

T1 - Exceptional damage-tolerance of a medium-entropy alloy CrCoNi at cryogenic temperatures

AU - Gludovatz, Bernd

AU - Hohenwarter, Anton

AU - Thurston, Keli V S

AU - Bei, Hongbin

AU - Wu, Zhenggang

AU - George, Easo P.

AU - Ritchie, Robert O.

PY - 2016/2/2

Y1 - 2016/2/2

N2 - High-entropy alloys are an intriguing new class of metallic materials that derive their properties from being multi-element systems that can crystallize as a single phase, despite containing high concentrations of five or more elements with different crystal structures. Here we examine an equiatomic medium-entropy alloy containing only three elements, CrCoNi, as a single-phase face-centred cubic solid solution, which displays strength-toughness properties that exceed those of all high-entropy alloys and most multi-phase alloys. At room temperature, the alloy shows tensile strengths of almost 1 GPa, failure strains of ∼70% and KJIc fracture-toughness values above 200 MPa m1/2; at cryogenic temperatures strength, ductility and toughness of the CrCoNi alloy improve to strength levels above 1.3 GPa, failure strains up to 90% and KJIc values of 275 MPa m1/2. Such properties appear to result from continuous steady strain hardening, which acts to suppress plastic instability, resulting from pronounced dislocation activity and deformation-induced nano-twinning.

AB - High-entropy alloys are an intriguing new class of metallic materials that derive their properties from being multi-element systems that can crystallize as a single phase, despite containing high concentrations of five or more elements with different crystal structures. Here we examine an equiatomic medium-entropy alloy containing only three elements, CrCoNi, as a single-phase face-centred cubic solid solution, which displays strength-toughness properties that exceed those of all high-entropy alloys and most multi-phase alloys. At room temperature, the alloy shows tensile strengths of almost 1 GPa, failure strains of ∼70% and KJIc fracture-toughness values above 200 MPa m1/2; at cryogenic temperatures strength, ductility and toughness of the CrCoNi alloy improve to strength levels above 1.3 GPa, failure strains up to 90% and KJIc values of 275 MPa m1/2. Such properties appear to result from continuous steady strain hardening, which acts to suppress plastic instability, resulting from pronounced dislocation activity and deformation-induced nano-twinning.

UR - http://www.scopus.com/inward/record.url?scp=84957584532&partnerID=8YFLogxK

U2 - 10.1038/ncomms10602

DO - 10.1038/ncomms10602

M3 - Article

AN - SCOPUS:84957584532

VL - 7.2016

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

M1 - 10602

ER -