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Title of project: A study on the evaluations of fatigue strength and materials integrity of hard surface coatings

项目名称：硬表面涂层疲劳强度和材料完整性评价研究

基本信息

批准号：
09650093
负责人：
OGAWA Takeshi
金额：
$ 2.24万
依托单位：
Aoyama Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09650093/
关键词：
Surface coating Fatigue strength Materials integrity Surface treatment Spraying

项目摘要

In the present study, fatigue strength and materials integrity of hard surface coatings have been evaluated. The coating material selected is a cermet (WC-12%Co) coating sprayed by high velocity oxygen fuel (HVOF) treatment. First rotating bending fatigue tests have been conducted at room temperature in laboratory air using specimens of medium carbon steel (S45C), low alloy steel (SCM435) and titanium alloy (Ti-6Al-4V) with the cermat sprayed coating and S45C with WFS sprayed coating of a 13Cr steel (SUS420J2). Plane bending fatigue tests were also conducted at stress ratios of 0, -0.5 and -1, The fatigue strength and fracture mechanisms were studied. Second, rolling contact fatigue of the WC-12%Co coated material was investigated on ring type plate specimen.Detailed observations of crack initiation and growth were performed and the results were compared with those obtained through stress distribution analysis performed by finite element method (FEM) and the crack initiation site was discussed, Third, inverse analysis of the velocity dispersion of laser excited surface acoustic wave (SAW) was used to estimate the elastic properties of three types of sprayed coatings, NiCrAlY, CrNiMoSiB and the WC-cermet. The obtained results were compared with those obtained by the mechanical methods of 3- or 4-point bending tests for the free standing specimen and/or sprayed specimen.Forth, with the aim of studying the effect of residual stress of the WC-cermet sprayed coating on fracture resistance, we evaluated the residual stresses of three coatings deposited by different spray conditions. AE monitoring and source characterization are utilized to study crack initiation and dynamics under quasi-static four-point bending condition.

在本研究中，评估了硬表面涂层的疲劳强度和材料完整性。所选涂层材料是经高速氧燃料（HVOF）处理喷涂的金属陶瓷（WC-12%Co）涂层。在室温下，在实验室空气中，使用带有金属陶瓷喷涂涂层的中碳钢（S45C）、低合金钢（SCM435）和钛合金（Ti-6Al-4V）样本以及带有13Cr钢（SUS420J2）WFS喷涂涂层的S45C样本进行了首次旋转弯曲疲劳试验。并在应力比为0、-0.5和-1时进行了平面弯曲疲劳试验，研究了疲劳强度和断裂机制。其次，在环形板试样上研究了 WC-12%Co 涂层材料的滚动接触疲劳。对裂纹萌生和扩展进行了详细观察，并将结果与有限元法 (FEM) 进行的应力分布分析所获得的结果进行了比较，并讨论了裂纹萌生位置。第三，利用激光激发表面声波 (SAW) 的速度色散反演分析来估计三种材料的弹性性能。喷涂涂层类型：NiCrAlY、CrNiMoSiB 和 WC 金属陶瓷。将所得结果与自立式试样和/或喷涂试样的三点或四点弯曲试验的机械方法进行比较。第四，为了研究WC-金属陶瓷喷涂层残余应力对断裂抗力的影响，我们评估了不同喷涂条件下沉积的三种涂层的残余应力。利用声发射监测和源表征来研究准静态四点弯曲条件下的裂纹萌生和动力学。