Surjadi James Utama, Gao Libo, Cao Ke, Fan Rong, Lu Yang
Department of Mechanical and Biomedical Engineering, City University of Hong Kong, Kowloon, Hong Kong.
Centre for Advanced Structural Materials (CASM), Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518057, China.
Sci Rep. 2018 Apr 3;8(1):5442. doi: 10.1038/s41598-018-23857-7.
Mechanical metamaterials such as microlattices are an emerging kind of new materials that utilize the combination of structural enhancement effect by geometrical modification and the intrinsic properties of its material constituents. Prior studies have reported the mechanical properties of ceramic or metal-coated composite lattices. However, the scalable synthesis and characterization of high-entropy alloy (HEA) as thin film coating for such cellular materials have not been studied previously. In this work, stereolithography was combined with Radio Frequency (RF) magnetron sputtering to conformally deposit a thin layer (800 nm) of CrMnFeCoNi HEA film onto a polymer template to produce HEA-coated three-dimensional (3D) core-shell microlattice structures for the first time. The presented polymer/HEA hybrid microlattice exhibits high specific compressive strength (0.018 MPa kg m) at a density well below 1000 kg m, significantly enhanced stiffness (>5 times), and superior elastic recoverability compared to its polymer counterpart due to its composite nature. The findings imply that this highly scalable and effective route to synthesizing HEA-coated microlattices have the potential to produce novel metamaterials with desirable properties to cater specialized engineering applications.
诸如微晶格之类的机械超材料是一种新兴的新型材料，它利用几何形状改性带来的结构增强效应与其材料成分的固有特性相结合。先前的研究报道了陶瓷或金属涂层复合晶格的力学性能。然而，此前尚未研究过高熵合金（HEA）作为此类多孔材料薄膜涂层的可扩展合成及表征。在这项工作中，将立体光刻与射频（RF）磁控溅射相结合，首次在聚合物模板上共形沉积了一层约800纳米厚的CrMnFeCoNi高熵合金薄膜，以制备高熵合金涂层的三维（3D）核壳微晶格结构。所展示的聚合物/高熵合金混合微晶格在密度远低于1000千克/立方米的情况下，表现出较高的比抗压强度（约0.018兆帕·千克/米），刚度显著提高（超过5倍），并且由于其复合性质，与聚合物对应物相比具有优异的弹性恢复能力。这些发现表明，这种高度可扩展且有效的合成高熵合金涂层微晶格的途径有潜力生产出具有理想性能的新型超材料，以满足特殊的工程应用需求。
