织构对超音速火焰喷涂涂层结合强度的影响
发布时间：2018-11-11 00:07
【摘要】：超音速火焰喷涂的WC-Co涂层具有优异的综合性能如孔隙率低、结合强度大、硬度高、耐磨性强等特点,近年来对超音速火焰喷涂研究得到了飞速的发展,取得了丰硕的成果。同样,由于表面织构能够改变基体表面的接触特性如耐磨性、降噪等。具有奇特的表面改性能力,研究织构对涂层结合强度的影响,对于提高界面结合强度、强化涂层防护性能、延长涂层使用寿命具有重要的理论意义和实用价值。本文主要研究内容如下:1.用单点金刚石划痕法在304不锈钢表面划出有规律的微米级沟槽,用超景深显微镜观察划痕表面形貌,观察不同划痕深度,划痕间距形貌区别。2.相比于无织构涂层,采用垂直拉伸法,用有限元模拟了不同参数化微织构对涂层/基体界面上拉应力分布影响。对切口附近应力集中进行有限元分析,为评价涂层与基体的结合性能提供依据。3.在已加工的沟槽表面进行超音速火焰喷涂WC-Co涂层,采用线切割在涂层/基体界面切割成U型切口,在涂层、基体和界面的平行边有相同尺寸的拉块粘结,然后在拉伸试验机上研究不同参数化织构对涂层的抗拉强度。得到涂层破坏时涂层和基体断裂的平均应力及涂层断裂的裂纹断裂扩展路径。研究的结果表明:在拉应力作用下,试样U形切口尖端应力集中明显,促进了高强度涂层/基体界面的脆性断裂,织构在相对合理的参数范围内能提高涂层的结合强度。
[Abstract]:The supersonic flame sprayed WC-Co coating has excellent comprehensive properties, such as low porosity, high bonding strength, high hardness, strong wear resistance and so on. In recent years, the research on supersonic flame spraying has been developed rapidly and fruitful results have been obtained. Similarly, the surface texture can change the contact characteristics of the matrix surface, such as wear resistance, noise reduction and so on. The effect of texture on the bonding strength of the coating is of great theoretical significance and practical value in improving the bonding strength of the coating, strengthening the protective properties of the coating and prolonging the service life of the coating. The main contents of this paper are as follows: 1. Regular micron grooves were made on 304 stainless steel surface by single point diamond scratch method. The surface morphology of scratches was observed by hyperfield depth microscope, and different scratch depth was observed. 2. Compared with the non-texture coating, the effect of different parameterized microtextures on the tensile stress distribution at the interface between the coating and the substrate was simulated by using the vertical tensile method and finite element method. The stress concentration near the notch is analyzed by finite element method, which provides a basis for evaluating the bonding properties of coating and substrate. The WC-Co coating was sprayed by supersonic flame on the machined grooves. A U-notch was cut by wire cutting at the interface of the coating / substrate, and the same size of the drawing block bonded on the coating, the parallel edge of the substrate and the interface. Then the tensile strength of the coating with different parameterized textures was studied on a tensile tester. The average stress of coating and substrate fracture and the crack propagation path of coating fracture are obtained. The results show that under the action of tensile stress, the stress concentration at the tip of the U-notch of the sample is obvious, which promotes the brittle fracture of the interface between the high strength coating and the substrate, and the texture can improve the bonding strength of the coating in a relatively reasonable range of parameters.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.44
[Abstract]:The supersonic flame sprayed WC-Co coating has excellent comprehensive properties, such as low porosity, high bonding strength, high hardness, strong wear resistance and so on. In recent years, the research on supersonic flame spraying has been developed rapidly and fruitful results have been obtained. Similarly, the surface texture can change the contact characteristics of the matrix surface, such as wear resistance, noise reduction and so on. The effect of texture on the bonding strength of the coating is of great theoretical significance and practical value in improving the bonding strength of the coating, strengthening the protective properties of the coating and prolonging the service life of the coating. The main contents of this paper are as follows: 1. Regular micron grooves were made on 304 stainless steel surface by single point diamond scratch method. The surface morphology of scratches was observed by hyperfield depth microscope, and different scratch depth was observed. 2. Compared with the non-texture coating, the effect of different parameterized microtextures on the tensile stress distribution at the interface between the coating and the substrate was simulated by using the vertical tensile method and finite element method. The stress concentration near the notch is analyzed by finite element method, which provides a basis for evaluating the bonding properties of coating and substrate. The WC-Co coating was sprayed by supersonic flame on the machined grooves. A U-notch was cut by wire cutting at the interface of the coating / substrate, and the same size of the drawing block bonded on the coating, the parallel edge of the substrate and the interface. Then the tensile strength of the coating with different parameterized textures was studied on a tensile tester. The average stress of coating and substrate fracture and the crack propagation path of coating fracture are obtained. The results show that under the action of tensile stress, the stress concentration at the tip of the U-notch of the sample is obvious, which promotes the brittle fracture of the interface between the high strength coating and the substrate, and the texture can improve the bonding strength of the coating in a relatively reasonable range of parameters.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG174.44
【参考文献】
相关期刊论文 前6条
1 张康;鲍君峰;王梦雨;;热喷涂技术在石油工业的应用[J];热喷涂技术;2015年01期
2 王东伟;莫继良;王正国;王晓翠;陈光雄;朱e，
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