Gómez-Cortés Jose F, Nó María L, Chuvilin Andrey, Ruiz-Larrea Isabel, San Juan Jose M
Departamento de Física, Facultad de Ciencia y Tecnología, Universidad del País Vasco (UPV/EHU), Apto. 644, 48080 Bilbao, Spain.
CIC NanoGUNE BRTA, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian, Spain.
Nanomaterials (Basel). 2023 Sep 21;13(18):2605. doi: 10.3390/nano13182605.
Cu-Al-Ni is a high-temperature shape memory alloy (HTSMA) with exceptional thermomechanical properties, making it an ideal active material for engineering new technologies able to operate at temperatures up to 200 °C. Recent studies revealed that these alloys exhibit a robust superelastic behavior at the nanometer scale, making them excellent candidates for developing a new generation of micro-/nano-electromechanical systems (MEMS/NEMS). The very large-scale integration (VLSI) technologies used in microelectronics are based on thin films. In the present work, 1 μm thickness thin films of 84.1Cu-12.4 Al-3.5Ni (wt.%) were obtained by solid-state diffusion from a multilayer system deposited on SiNx (200 nm)/Si substrates by e-beam evaporation. With the aim of evaluating the thermal stability of such HTSMA thin films, heating experiments were performed in situ inside the transmission electron microscope to identify the temperature at which the material was decomposed by precipitation. Their microstructure, compositional analysis, and phase identification were characterized by scanning and transmission electron microscopy equipped with energy dispersive X-ray spectrometers. The nucleation and growth of two stable phases, Cu-Al-rich alpha phase and Ni-Al-rich intermetallic, were identified during in situ heating TEM experiments between 280 and 450 °C. These findings show that the used production method produces an HTSMA with high thermal stability and paves the road for developing high-temperature MEMS/NEMS using shape memory and superelastic technologies.
铜铝镍是一种高温形状记忆合金（HTSMA），具有卓越的热机械性能，使其成为用于开发能够在高达200°C温度下运行的新技术的理想活性材料。最近的研究表明，这些合金在纳米尺度上表现出强大的超弹性行为，使其成为开发新一代微/纳米机电系统（MEMS/NEMS）的优秀候选材料。微电子中使用的超大规模集成（VLSI）技术基于薄膜。在本工作中，通过电子束蒸发在SiNx（200nm）/Si衬底上沉积的多层系统经固态扩散获得了厚度为1μm的84.1Cu-12.4Al-3.5Ni（重量百分比）薄膜。为了评估这种HTSMA薄膜的热稳定性，在透射电子显微镜内原位进行加热实验，以确定材料因析出而分解的温度。通过配备能量色散X射线光谱仪的扫描和透射电子显微镜对其微观结构、成分分析和相鉴定进行了表征。在280至450°C的原位加热TEM实验中，确定了两种稳定相的形核和生长，即富铜铝的α相和富镍铝的金属间化合物。这些发现表明，所采用的生产方法制备出了具有高热稳定性的HTSMA，并为利用形状记忆和超弹性技术开发高温MEMS/NEMS铺平了道路。
