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DOE OSTI · 3740826

Atomic faulting drives exceptional toughness in low thermal expansion chromium alloys

Abstract

Endowing functional properties with mechanical responses in traditional metals has been a frontier topic, akin to transforming base metal into gold. Chromium and its alloys, with their functional deficiencies and limited ductility, serve as typical examples. Herein, we report a Cr96Fe4Ge1.3B1 alloy that unifies low thermal expansion (LTE, αl = 1.79 × 10-6 K-1, 200 − 315 K) with exceptional toughness (240.2 J·cm-3). The enhancement in mechanical responses is primarily attributed to layered Cr2B intermetallic precipitates, which ameliorate interfacial cohesion and simultaneously refine the grain structure. The weakened interlayer interactions within the Cr-B layers facilitate the nucleation and movement of numerous tiny stacking faults in precipitates, efficiently alleviating strain energy and resulting in marked work-hardening ability. Additionally, antiferromagnetic fluctuations in the BCC matrix contribute to the unique LTE behavior. This paves the way for the design of high-performance alloys featuring layered-symmetry precipitates.

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Yu, Chengyi [University of Science and Technology Beijing, China], Wu, Honghui [University of Science and Technology Beijing], Zhu, Huihui [University of Science and Technology Beijing], Chen, Xin [University of Science and Technology Beijing, China], Zhang, Qinghua [Chinese Academy of Sciences (CAS)], Gu, Lin [Chinese Academy of Sciences], Frontzek, Matthias [ORNL] (ORCID:0000000187048928), Chen, Yan [ORNL] (ORCID:0000000160951754), An, Ke [ORNL] (ORCID:000000026093429X), He, Lunhua [China Spallation Neutron Source, Guangdong, China], Kato, Kenichi [RIKEN SPring- 8 Center], Kawaguchi, Shogo [RIKEN SPring-8 Center (RSC), Japan], Qiao, Zeyu [University of Science and Technology Beijing], Zhou, Meisa [University of Science and Technology Beijing], Cao, Yili [University of Science and Technology Beijing, China], Li, Qiang [University of Science and Technology Beijing, China], Deng, Jinxia [University of Science and Technology Beijing, China], Lin, Kun [University of Science and Technology Beijing, China], Xing, Xianran [University of Science and Technology Beijing, China], Zhang, Qiang [ORNL] (ORCID:0000000303897039), Chen, Yujie [Tsinghua University, China]. 2026-02-01. Atomic faulting drives exceptional toughness in low thermal expansion chromium alloys. https://doi.org/10.1038/s41467-026-69365-5

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