ABSTRACT

The current metamaterials with the programmable coefficient of thermal expansion (CTE) usually present the unexpected anisotropy, and the experimentally measured CTEs are quite narrower. Here, a bi-material metamaterial was constructed. The material extrusion process was established to fabricate the metamaterial. The measured CTEs in various in-plane directions are in good consistency to each other, experimentally verifying the identical CTE in various in-plane directions. The relative deviation between the experimental measurements and theoretical predictions is within −13.0% to +11.0%. The positive programmable CTEs are as high as 204 and 258 ppm/°C, which are larger than those of the basic polymers nylon and polyvinyl alcohol (PVA). Otherwise, the negative CTEs of −25 and −77 ppm/°C are obtained, even though both the nylon and PVA have positive CTEs. The programmable CTEs are expanded to be [−77, +258] ppm/°C, far beyond the literature results, supplementing the additive manufacturing and experimental basis to the engineering applications.

摘要

当前具有可编程热膨胀系数 (CTE) 的超材料通常表现出意想不到的各向异性，并且实验测量的 CTE 非常窄。在这里，构建了一种双材料超材料。建立材料挤压工艺来制造超材料。测得的各个面内方向的CTE具有良好的一致性，通过实验验证了各个面内方向的CTE相同。实验测量和理论预测之间的相对偏差在 -13.0% 到 +11.0% 之间。正可编程 CTE 高达 204 和 258 ppm/°C，大于基本聚合物尼龙和聚乙烯醇 (PVA) 的 CTE。否则，将获得 -25 和 -77 ppm/°C 的负 CTE，即使尼龙和 PVA 都具有正 CTE。可编程 CTE 扩展到 [−77, +258] ppm/°C，远远超出文献结果，为工程应用补充了增材制造和实验基础。