The hard thin films are often subjected to high loading in the engineering applications. The circumferential cracks, formed under contact loading, usually occur from film surface and extend to the interface between hard thin films and ductile substrates, which affect the reliability and stability of the materials. Furthermore, the great residual stress in the hard thin films influences the film-substrate interface, even resulting in the failure of the interface. In this paper, the effect of residual stress on the indentation-induced circumferential cracks of the hard thin films deposited on ductile substrates is simulated by the cohesive model and finite element method. The radius of circumferential cracks, crack spacing, critical indentation depth and indentation load under alterable residual stress are obtained when the circumferential cracks occur, indicating the failure mechanism induced by indentation. This provides guidelines for the measurement of fracture toughness of the film by using indentation and the engineering applications.%近年来,随着制备工艺的革新,硬质薄膜作为保护涂层已有了广泛的应用.在实际使用过程中,硬质涂层经常承受接触载荷作用.薄膜在接触载荷下易产生环形裂纹,从薄膜的表面起裂并扩展到界面,从而影响材料的可靠性和稳定性.同时,硬质薄膜中的残余应力的存在也将直接影响薄膜的服役周期.基于内聚力模型,采用有限元方法模拟来探究残余应力对压头诱导的硬质薄膜/韧性基底中薄膜本身断裂的影响规律.给出在不同残余应力下薄膜发生环形裂纹的起裂半径、裂纹间距、临界压入深度以及临界载荷,进而对运用压痕法测量薄膜的断裂韧性和工程应用提供指导.
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