Department of Industrial and Materials Science, Chalmers University of Technology, SE-41296, Gothenburg, Sweden.
Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296, Gothenburg, Sweden.
Adv Mater. 2019 Jan;31(2):e1805392. doi: 10.1002/adma.201805392. Epub 2018 Nov 8.
Designing alloys with an accurate temperature-independent electrical response over a wide temperature range, specifically a low temperature coefficient of resistance (TCR), remains a big challenge from a material design point of view. More than a century after their discovery, Constantan (Cu-Ni) and Manganin (Cu-Mn-Ni) alloys remain the top choice for strain gauge applications and high-quality resistors up to 473-573 K. Here, an average TCR is demonstrated that is up to ≈800 times smaller in the temperature range 5-300 K and >800 times smaller than for any of these standard materials over a wide temperature range (5 K < T < 1200 K). This is achieved for selected compositions of Al CoCrFeNi high-entropy alloys (HEAs), for which a strong correlation of the ultralow TCR is established with the underlying microstructure and its local composition. The exceptionally low electron-phonon coupling expected in these HEAs is crucial for developing novel devices, e.g., hot-electron detectors, high-Q resonant antennas, and materials in gravitational wave detectors.
设计在宽温度范围内具有准确的温度独立电响应的合金,特别是低电阻温度系数 (TCR),从材料设计的角度来看仍然是一个巨大的挑战。在发现它们一个多世纪后,康斯坦坦(Cu-Ni)和锰铜(Cu-Mn-Ni)合金仍然是应变计应用和高达 473-573 K 的高质量电阻器的首选。在这里,展示了一种平均 TCR,在 5-300 K 的温度范围内,其 TCR 小了约 800 倍,在很宽的温度范围内(5 K < T < 1200 K),其 TCR 小了 800 倍以上。这是通过选择 AlCoCrFeNi 高熵合金 (HEA) 的成分来实现的,对于这些 HEA,已经建立了超低 TCR 与基础微观结构及其局部成分之间的强相关性。这些 HEA 中预期的极低电子-声子耦合对于开发新型器件至关重要,例如热电子探测器、高 Q 共振天线以及引力波探测器中的材料。