Study on Fatigue Strength of Ceramics and Ceramics Coating Materials Using Laser Aided Strain Monitoring Technique

利用激光辅助应变监测技术研究陶瓷及陶瓷涂层材料的疲劳强度

基本信息

批准号：
08650109
负责人：
NISHIKAWA Izuru
金额：
$ 1.41万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08650109/
关键词：
Ceramics Ceramics Coating Fatigue strength High temperature Static Cyclic Fatigue Laser Speckle Crack Closure Bridging

项目摘要

Fatigue strength of ceramics and ceramics-coated materials were studied in this study. Crack growth tests for alumina ceramics and silicon nitride ceramics were performed at both room and elevated temperature. The crack opening displacement was also measured during the tests. Then the crack growth characteristics of ceramics were discussed using these experimental data. The results obtained from this study are s follows.1. The crack growth rate was found to decrease gradually with a further crack growth, and after some crack extension a crack stopped growing temporary in both ceramics materials.2. It was found from the relationship between crack opening displacement and stress intensity factor that a crack opening level, Kop, increased with increase in the number of cycles. A little bit wide hysteresis was also observed in these relations. These hysteresis were thought to correspond with the effect of the particle bridging on the crack opening behavior. Furthermore, the compliance of s … More ample varied discontinuously during a fatigue test.3. Both the crack arrest mentioned the above and the variation on the compliance related to the influence of the particle bridging near the crack tip. The stress intensity factor at crack tip was reduced by subtracting the friction stress due to this bridging effect.Next, fatigue tests for ceramics coating materials were conducted at both room and elevated temperature. The results for coating materials are as follows.1. While the blasted sample at room temperature has a higher fatigue limit than the annealed sample at the same temperature, the alumina coated sample has a lower fatigue limit than the blasted sample.2. Though the ceramics coated sample shows the elastic deformation at an early stage of fatigue life under a higher applied stress level, the plastic deformation increased with increase in the number of cycles at a middle stage of fatigue life. This behavior corresponded with the cyclic softening behavior of substrate. At a final stage of fatigue life the surface strain of the sample varied discontinuously. This means that the region with no strain due to the delamination among a coat material and a substrate appeared.3. Under a lower applied stress level, the sample was under an elastic state at an early stage, and gradually showed the plastic deformation behavior. At a final stage of fatigue life, however, the plastic strain range of sample decreased with increasing the number of cycles. This means that a single main crack can only propagate under this condition. Less

在这项研究中研究了陶瓷和陶瓷涂层材料的疲劳强度。氧化铝陶瓷和氮化硅陶瓷的裂纹生长试验均在房间和温度升高时进行。在测试期间还测量了裂纹开口位移。然后使用这些实验数据讨论了陶瓷的裂纹生长特征。从这项研究中获得的结果s以下1。发现裂纹的生长速率随着裂纹的进一步生长而逐渐降低，在裂纹延伸后，裂纹在两种陶瓷材料中都停止了临时生长。2。从裂缝开口位移和应力强度因子之间的关系中发现，裂纹开口水平，KOP随着周期数量的增加而增加。在这些关系中也观察到了一些较广泛的滞后。这些滞后被认为与粒子桥接对裂纹开口行为的影响相对应。此外，在疲劳测试期间，S…的遵守情况更加不连续。3。裂纹逮捕都提到了上述内容和依从性的变化，与裂纹尖端附近桥接的影响有关。通过减去由于这种桥接效果而减少裂纹尖端的应力强度因子。隔离，在房间和温度升高的情况下进行了陶瓷涂料材料的疲劳测试。涂料材料的结果如下1。虽然室温下的爆炸样品的疲劳极限高于在同一温度下退火样品，但铝涂层样品的疲劳极限低于爆炸样品。2。尽管陶瓷涂层样品显示在疲劳寿命的早期阶段的弹性变形在较高的应力水平下，但塑性变形随着疲劳寿命中阶段的周期数量的增加而增加。行为与底物的环形软化行为相对应。在疲劳寿命的最后阶段，样品的表面应变不连续。这意味着由于外套材料和底物的分层而没有应变的区域出现3。在较低的施加应力水平下，样品在早期处于弹性状态，并逐渐显示出塑性变形行为。然而，在疲劳寿命的最后阶段，样品的塑性应变范围随着周期数量的增加而降低。这意味着单个主裂纹只能在这种情况下传播。较少的