Abstract Fracture behaviors of thin hard diamond-like carbon (DLC) films were investigated considering the effects of plastic deformation of steel substrates. Nano-indentation tests for DLC films on SUS304 and M50 steels were conducted. The nucleation and propagation of film cracks were analyzed using the extended finite element method (XFEM). The ultimate tensile strength, fracture energy release rate and toughness of the films were evaluated. Results showed that cracks in DLC films on M50 steel substrates nucleated on the top surface of the films during nano-indentation; however, the first crack initiated at the bottom surface of DLC films on SUS304 steel because of its low yield strength. Large plastic deformation of the steel substrate was generated under nano-indentation, leading to consequent high tensile stress that concentrated first at the bottom surface of the films due to the film bending effect.

中文翻译：

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纳米压痕过程中钢基体类金刚石碳膜的裂纹演变

摘要 考虑钢基体塑性变形的影响，研究了硬质类金刚石碳（DLC）薄膜的断裂行为。对 SUS304 和 M50 钢上的 DLC 薄膜进行了纳米压痕测试。使用扩展有限元方法（XFEM）分析膜裂纹的成核和扩展。评估了薄膜的极限拉伸强度、断裂能释放率和韧性。结果表明，在纳米压痕过程中，M50钢基体上DLC薄膜的裂纹在薄膜的上表面成核；然而，由于 SUS304 钢的屈服强度低，第一次裂纹在 DLC 膜的底面开始。钢基体在纳米压痕下产生较大的塑性变形，