Xu Meng, Li Qiang, Song Yuzhu, Xu Yuanji, Sanson Andrea, Shi Naike, Wang Na, Sun Qiang, Wang Changtian, Chen Xin, Qiao Yongqiang, Long Feixiang, Liu Hui, Zhang Qiang, Venier Alessandro, Ren Yang, d'Acapito Francesco, Olivi Luca, De Souza Danilo Oliveira, Xing Xianran, Chen Jun
Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, China.
Institute of Solid State Chemistry, University of Science and Technology Beijing, Beijing, 100083, China.
Nat Commun. 2023 Jul 24;14(1):4439. doi: 10.1038/s41467-023-40074-7.
Negative thermal expansion (NTE) alloys possess great practical merit as thermal offsets for positive thermal expansion due to its metallic properties. However, achieving a large NTE with a wide temperature range remains a great challenge. Herein, a metallic framework-like material FeZr is found to exhibit a giant uniaxial (1D) NTE with a wide temperature range (93-1078 K, [Formula: see text]). Such uniaxial NTE is the strongest in all metal-based NTE materials. The direct experimental evidence and DFT calculations reveal that the origin of giant NTE is the couple with phonons, flexible framework-like structure, and soft bonds. Interestingly, the present metallic FeZr excites giant 1D NTE mainly driven by high-frequency optical branches. It is unlike the NTE in traditional framework materials, which are generally dominated by low energy acoustic branches. In the present study, a giant uniaxial NTE alloy is reported, and the complex mechanism has been revealed. It is of great significance for understanding the nature of thermal expansion and guiding the regulation of thermal expansion.
负热膨胀（NTE）合金由于其金属特性，作为正热膨胀的热补偿具有很大的实际价值。然而，在宽温度范围内实现大的负热膨胀仍然是一个巨大的挑战。在此，发现一种金属骨架状材料FeZr在宽温度范围（93 - 1078 K，[公式：见原文]）内表现出巨大的单轴（一维）负热膨胀。这种单轴负热膨胀在所有金属基负热膨胀材料中是最强的。直接的实验证据和密度泛函理论计算表明，巨大负热膨胀的起源是与声子的耦合、柔性骨架状结构和软键。有趣的是，目前的金属FeZr激发巨大的一维负热膨胀主要由高频光学支驱动。这与传统骨架材料中的负热膨胀不同，传统骨架材料中的负热膨胀通常由低能声学支主导。在本研究中，报道了一种巨大的单轴负热膨胀合金，并揭示了其复杂机制。这对于理解热膨胀的本质和指导热膨胀调控具有重要意义。
