Cr–Si–N coatings were prepared through reactive direct current magneton sputtering using a high N2/Ar flow ratio of 1. The addition of Si to improve the mechanical properties and oxidation resistance of Cr–N coatings was examined. The results indicated that the Cr–Si–N coatings with an Si content of <12 at % and an N content of >50 at % exhibited a cubic CrN phase with a columnar structure, whereas the coatings with 14 at % Si comprised of a nanocomposite structure, and the coatings with 16–18 at % Si were near-amorphous. The nanocomposite Cr32Si14N54 coating possessed hardness and Young’s modulus values of 17 and 209 GPa, respectively, accompanied with a hardness to effective Young’s modulus (H/E*) value of 0.077 and an elastic recovery (We) level of 55%—all the properties were highest within the as-deposited coating. The addition of Si was also beneficial to reduce the surface roughness and improve the oxidation resistance.

With the development of metamaterials, tunable auxetic structures have attracted extensive attention due to their unusual mechanical behaviors. In this study, we design and 3D print an auxetic shape-memory dual-moiety structure, and achieve a reversible and sequential buckling behavior by means of the local instability. Effects of hollowness radius, Young's modulus ratio and temperature on the buckling behavior of this auxetic dual-moiety structure have been studied by the finite element method analysis. The constitutive relationships between stress, strain, hollowness radius and Young's modulus have been presented and discussed. Finally, the buckling behaviors have been investigated by the mechanical tests, and the accuracy of numerical results has then been verified by using the experimentally obtained data. This study is expected to provide a design guideline for auxetic dual-moiety structure with sequentially tunable buckling behaviors by means of twofold viscoelastic resonances.

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