| 引用本文: | 袁晓静,查柏林,姚春江,陈小虎,郑燃,王新军.基于微观结构的热喷涂WC/Co涂层裂纹生长模拟[J].材料科学与工艺,2019,27(2):70-76.DOI:10.11951/j.issn.1005-0299.20170203. |
| YUAN Xiaojing,ZHA Bailin,YAO Chunjiang,CHEN Xiaohu,ZHENG Ran,WANG Xinjun.Modeling of fatigue crack growth on the microstructure for thermal sprayed WC/Co coatings[J].Materials Science and Technology,2019,27(2):70-76.DOI:10.11951/j.issn.1005-0299.20170203. |
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| 摘要: |
| 涂层微观结构特征直接影响涂层的寿命，基于涂层微观结构研究涂层裂纹扩展特征成为评价热喷涂层性能的重要问题.本文基于WC/Co涂层微观结构建立了有限元模型，并采用XFEM方法研究了单应力状态预存裂纹行了模拟，获得了涂层微观裂纹扩展的损伤规律.研究表明：在拉应力作用下，沿着WC-Co边界产生的应力集中是涂层裂纹产生的根源；WC/Co涂层浅表面(0.125b，b为涂层厚度)的水平裂纹对垂直拉应力敏感、吸收能量快，0.78b处的裂纹扩展后对应力响应迅速，因此0.125b与0.78b是WC/Co涂层裂纹生长的关键深度；在0.78b处，当初始裂纹角度0°~45°时，扩展位移逐渐减小，扩展偏转角增大，45°时存在能量积累导致角度快速偏转.在周期应力作用时，WC/Co涂层的疲劳周期随应变幅值增加而减小；应变幅值相同时，WC/Co涂层的疲劳周期随频率增加而增加. |
| 关键词: 裂纹 有限元模拟 真实结构 等效参数 WC/Co涂层 |
| DOI：10.11951/j.issn.1005-0299.20170203 |
| 分类号:TG174.4 |
| 文献标识码:A |
| 基金项目:国家自然科学基金资助项目(51405497). |
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| Modeling of fatigue crack growth on the microstructure for thermal sprayed WC/Co coatings |
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YUAN Xiaojing, ZHA Bailin, YAO Chunjiang, CHEN Xiaohu, ZHENG Ran, WANG Xinjun
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(501 staff, Rocket Military Engineering University, Xi′an 710025, China)
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| Abstract: |
| Since the microstructure characteristics of a coating have direct effects on the life of the coating, it is important to study the crack growth characteristics based on the microstructure of coatings for evaluating the properties of the thermal sprayed coatings. In this paper, a finite element model is established based on the microstructure of WC/Co coatings. The crack propagation in single stress state was simulated by XFEM method and the damage rules of the microscopic crack growth were obtained. Results show that the stress concentration along the WC-Co boundary under tensile stress was the root of cracks in the coatings. The horizontal cracks on the surface of WC/Co coatings (0.125b, b is the thickness of coatings) were sensitive to vertical tensile stress and they absorbed energy faster. The crack growth at 0.78b had a rapid response to stress, so 0.125b and 0.78b were critical depths of crack damage in WC/Co coatings. At 0.78b, when the initial crack angle was 0°~45°, the expansion displacement gradually decreased and the expansion deflection angle increased. When the initial crack angle was 45°, the energy accumulation caused the angle deflecting rapidly. Under cyclic stress, the fatigue cycle of WC/Co coatings decreased with the increase of strain amplitude. At the same strain amplitude, the fatigue cycle of WC/Co coatings increased with increasing strain. |
| Key words: crack finite element simulation real structure effective parameter WC/Co coatings |
