Investigation on Fatigue Strength of Nano/Micromatereials Subjected to Very High Cycle Fatigue

纳米/微米材料高周疲劳疲劳强度研究

• 批准号: 18560095
• 负责人: CHEN Qiang
• 金额: $ 2.41万
• 依托单位: Kochi National College of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560095/
• 关键词: Fatigue; Nano; Micromaterials; Crack Initiation; Very High Cycle; Thin Film

The application of silicon-based MEMS/NEMS has already resulted in significant improvements in our lives. Micromechanical components are routinely subjected to cyclic stresses at kilo- and megahertz frequencies, accumulating large numbers of stress cycles. To ensure performance and reliability of these tiny systems, fatigue mechanism must be elucidated to account for the timely and cyclically dependent degradation of the material at the size-scales of interest.In the present study, fatigue strength and fracture mechanism of LP_CVD polycrystalline silicon thin films were investigated in the domain of 10^7-10^9 cycles by using a novel strain controlled, piezoelectric actuated free standing tensile fatigue system that can installed either within or outside a scanning electron microscope (SEM). Fatigue small crack behavior were observed and taped by CCD video camera. The following results were obtained and the possible mechanism was discussed.A) The piezoelectric actuated tensile fatigue s … More ystem developed in the present study possesses a position sensor, which was fabricated by MEMS technology and can be used to monitor the movement of specimen center during cyclic loading.B) The geometry design of the free standing tensile specimen was optimized with the help of commercial FEM software, ANSYS, in terms of the maximum stress available at the center beam of the specimen and the minimum out of plane displacement occurred accordingly.C) It was fund that LP-CVD polycrystalline silicon thin films fatigued even at room temperature (~20℃) and at atmospheric environment (~26-35% of humidity). However, S-N diagram scattered tremendously, implying that the fatigue strength of the LP-CVD polycrystalline silicon thin films was quite sensitive to the difference in specimen morphology caused by micromachining as well as the deviation of humidity.D) Specimens failed with little remarkable damage evolution that can be recognized by either an optical or an electron microscope. Furthermore, limited fractographic analysis assumes that fatigue nucleation and early growth are localized, and the other fracture morphologies are most brittle featured. In other words, the most of fatigue life was consumed in nucleating tiny cracks. Less

硅基MEMS/NEMS的应用已经显著改善了我们的生活。微机械部件通常会受到千赫和兆赫频率的循环应力，累积大量的应力循环。为了保证这些微小系统的性能和可靠性，必须阐明疲劳机制，以解释材料在感兴趣的尺寸尺度上的时间和周期依赖性退化。压电致动的独立式拉伸疲劳系统，可以安装在扫描电子显微镜（SEM）内或外。用CCD摄像机对疲劳小裂纹行为进行了观察和录像。结果表明：（1）压电驱动的拉伸疲劳试验表明，压电驱动的拉伸疲劳裂纹扩展速度快，裂纹扩展速度快; ...更多信息 本研究中开发的悬臂梁具有一个位置传感器，该传感器采用MEMS技术制造，可用于监测循环加载过程中试样中心的移动。B）借助商业有限元软件ANSYS优化了自支撑拉伸试样的几何设计，根据试样中心梁处的最大应力和相应的最小平面外位移，发现LP-CVD多晶硅薄膜即使在室温（~20℃）和大气环境（~26-35%湿度）下也会发生疲劳。然而，S-N图的离散度很大，这意味着LP-CVD多晶硅薄膜的疲劳强度对微机械加工引起的试样形貌差异以及湿度偏差非常敏感。D）试样失效时几乎没有明显的损伤演化，这可以通过光学或电子显微镜来识别。此外，有限的断口分析假设，疲劳形核和早期增长是本地化的，和其他断口形貌是最脆的功能。换句话说，疲劳寿命的大部分消耗在成核微裂纹上。少

项目成果

LP-CVDポリシリコン薄膜の疲労特性

LP-CVD多晶硅薄膜的疲劳性能

• 发表时间: 2009
• 作者: 前田;小松;仮谷;村井;楠川;陳
• 通讯作者: 陳

薄膜材料の引張疲労における応力解析

薄膜材料拉伸疲劳应力分析

• 发表时间: 2009
• 作者: 吉村;武智;村井;楠川;仮谷;陳
• 通讯作者: 陳

LP-CVDポリシリコン薄膜材の繰返し引張り疲労

LP-CVD多晶硅薄膜材料的重复拉伸疲劳

• 发表时间: 2009
• 作者: 武智;陳強;楠川;刈谷;大平;鈴木
• 通讯作者: 鈴木

Fatigue Behavior of LP-CVD Polycrystalline Silicon Thin Film under Cyclic Tension

LP-CVD多晶硅薄膜循环张力下的疲劳行为

• 发表时间: 2009
• 作者: K. Takechi;Q. Chen;K. Kusukawa;S. Kariya;M. Ohira;K. Suzuki
• 通讯作者: K. Suzuki

Fatigue Behavior of LP-CVD Polycrystalline Silicon Thin Film

LP-CVD多晶硅薄膜的疲劳行为

• 发表时间: 2009
• 作者: S. Maeda;H. Komatsu;S. Kariya;M. Murai;K. Kusukawa;Q. Chen
• 通讯作者: Q. Chen