Atomic faulting drives exceptional toughness in low thermal expansion chromium alloys.
biomechanical · Level V
Where this comes from
- Record sourced from PubMed, PMID 41651842.
- Also identified by DOI 10.1038/s41467-026-69365-5 and PMC identifier 12988168.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 Cr<sub>96</sub>Fe<sub>4</sub>Ge<sub>1.3</sub>B<sub>1</sub> alloy that unifies low thermal expansion (LTE, α<sub>l</sub> = 1.79 × 10<sup>-6 </sup>K<sup>-1</sup>, 200 - 315 K) with exceptional toughness (240.2 J·cm<sup>-3</sup>). The enhancement in mechanical responses is primarily attributed to layered Cr<sub>2</sub>B 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.