Atomic-Scale In Situ Observations of Reversible Phase Transformation Assisted Twinning in a CrCoNi Medium-Entropy Alloy

Chu, Shufen1,2; Zhang, Fan3; Chen, Dengke4; Chen, Mingwei5,6; Liu, Pan1,2

2024-02-29

10.1021/acs.nanolett.3c04516

NANO LETTERS   影响因子和分区

1530-6984

1530-6992

Twinning is an important deformation mode of face-centered-cubic (FCC) medium- and high-entropy alloys, especially under extreme loading conditions. However, the twinning mechanism in these alloys that have a low or even negative stacking fault energy remains debated. Here, we report atomic-scale in situ observations of the deformation process of a prototypical CrCoNi medium-entropy alloy under tension. We found that the parent FCC phase first transforms into a hexagonal close-packed (HCP) phase through Shockley partial dislocations slipping on the alternate {111} planes. Subsequently, the HCP phase rapidly changes to an FCC twin band. Such reversible phase transformation assisted twinning is greatly promoted by external tensile loads, as elucidated by geometric phase analysis. These results indicate the previously underestimated role of the metastable HCP phase in nanotwin nucleation and early plastic deformations of CrCoNi alloys and shed light on microstructure regulation of medium-entropy alloys with enhanced mechanical properties.

medium-entropy alloy twinning phase transformation in situ transmission electron microscopy

SCI ; EI

英语

通讯

National Science Foundation[52271141] ; National Natural Science Foundation of China[21ZR1431200] ; Eastern Scholar Program at Shanghai Institutions of Higher Learning[NSF-DMR-1804320] ; National Science Foundation[WDZC2022-1]

Chemistry ; Science & Technology - Other Topics ; Materials Science ; Physics

Chemistry, Multidisciplinary ; Chemistry, Physical ; Nanoscience & Nanotechnology ; Materials Science, Multidisciplinary ; Physics, Applied ; Physics, Condensed Matter

WOS:001179627600001

AMER CHEMICAL SOC

MATERIALS SCIENCE

Web of Science

1.Shanghai Jiao Tong Univ, Sch Mat Sci & Engn, Shanghai Key Lab Adv High Temp Mat & Precis Formin, State Key Lab Met Matrix Composites, Shanghai 200240, Peoples R China
2.Shanghai Jiao Tong Univ JA Solar New Energy Mat Jo, Shanghai 200240, Peoples R China
3.Beijing Inst Technol, Sch Mat Sci & Engn, Beijing 100081, Peoples R China
4.Shanghai Jiao Tong Univ, Sch Naval Architecture Ocean & Civil Engn, Dept Engn Mech, Shanghai 200240, Peoples R China
5.Johns Hopkins Univ, Dept Mat Sci & Engn, Baltimore, MD 21218 USA
6.Southern Univ Sci & Technol, Coll Engn, Dept Mat Sci & Engn, Shenzhen 518055, Peoples R China

Chu, Shufen,Zhang, Fan,Chen, Dengke,et al. Atomic-Scale In Situ Observations of Reversible Phase Transformation Assisted Twinning in a CrCoNi Medium-Entropy Alloy[J]. NANO LETTERS,2024,24(12).

Chu, Shufen,Zhang, Fan,Chen, Dengke,Chen, Mingwei,&Liu, Pan.(2024).Atomic-Scale In Situ Observations of Reversible Phase Transformation Assisted Twinning in a CrCoNi Medium-Entropy Alloy.NANO LETTERS,24(12).

Chu, Shufen,et al."Atomic-Scale In Situ Observations of Reversible Phase Transformation Assisted Twinning in a CrCoNi Medium-Entropy Alloy".NANO LETTERS 24.12(2024).