内燃机阀门断裂失效分析

本文应用扫描电子显微镜、光学显微镜、直读光谱仪等对早期断裂失效的阀杆断口、阀门材料的成分、组织及阀门的服役状况进行检测、分析，确定断裂性质及产生原因。     

微电子器件金属化系统失效的电子显微分析

随着微电子器件向着超高频,超高速和高集成度化方向发展,电徒动引起的器件金属化系统失效问题变得日益突出。所谓电徒动是指高电流密度作用下,金属导体中发生质量输运的现象。电徒动使器件的内部金属化系统条状铝薄膜上出现小丘。晶须(质量堆积)和空洞(质量耗尽)现象,造成短路和开路失效。本文叙述了AL-Cu金属化系统电徒动寿命的测试和电镜分析。从实验获得了在300C.氮气环境中,高电流密度(0.6×10~6和1.2×10~6A.cm~(-2)作用下的Al-Cu薄膜电阻随时间的变化率,并计算了薄膜中值电徒动失效前的时间。用SEM和TEM观察和分析了钝化层覆盖效应,电流应力和晶粒结构等因素对     

髁支持接骨板的断裂失效分析

本文就一例置人病人体内髁支持接骨板的断裂失效事件，研究分析了髁支持接骨板断裂失效的原因，揭示了钢板质量的重要性。     

磁粉探伤旋转支撑辊传动轴断裂的失效分析

某公司磁粉探伤旋转支撑辊（主动辊）的传动轴仅运行2h就发生横向断裂，断轴宏观形貌见图1（箭头所指部位为断裂端，另一半断在轴承中），断轴横截面断口形貌见图2，在断口上有一肉眼可见的较大光滑孔洞，孔洞的直径约6mm左右，整个横截面断口上有大量的二次裂纹，断口平齐无变形。     

Failure mechanism models for brittle fracture

This tutorial illustrates designs where brittle fracture can endanger system performance, thereby acting as an overstress failure mechanism. Analytic (physics-of-failure) methods, based on continuum fracture-mechanisms rather than on molecular micro-mechanics, are presented to design against such failures. The associated stress-analysis techniques and material characterizations have matured appreciably over the past 40 years and are routinely used in aerospace, automotive, and other mechanical/structural applications. Two examples illustrate the use of these models in practical electronic packaging     

Failure mechanism models for ductile fracture

This tutorial illustrates design situations where ductile fracture of some components can compromise system performance, thereby acting as an overstress failure mechanism. Analytic (physics-of-failure) methods, based on continuum fracture mechanics principles, are presented to design against such failures. Examples illustrate the use of these models in practical design situations in mechanical engineering and electronic packaging. The design equations are based on continuum mechanics rather than on molecular micromechanics, and can be implemented in an engineering design environment. The associated stress analysis of ten requires numerical finite-element techniques. The methods for material-property characterizations have matured appreciably over the past 40 years and are specified in engineering handbooks     

钛阳极涂层溶蚀失效的研究

20世纪60年代末成功研制的Ti／RuO2氧化物涂层钛阳极(简称DSA)，因其良好的电化学性能，强的耐蚀性，电解服役的大部分过程能保持性能与外形尺寸稳定，很快就被人们认可。时至今日，世界已有80％以上的氯碱工业采用了它，并已迅速推至氯酸盐、水电解、湿法冶金、阳极保护等领域。     

脉冲光纤激光加工36MnVS4连杆裂解槽的研究

为了获得新材料36 MnVS4连杆裂解槽的最优切割质量,采用光纤激光器对36 MnVS4连杆进行了裂解槽激光加工的工艺研究,分析了离焦量、峰值功率、脉冲宽度、切割速度和脉冲频率对裂解槽几何尺寸的影响,通过激光共聚焦显微镜测量对比,研究不同激光工艺参数下裂解槽几何尺寸的变化规律。结果表明:负离焦能加工出质量更好的裂解槽;峰值功率、脉冲宽度、脉冲频率和切割速度对槽深和张角的影响较大,对槽宽和曲率半径的影响较小,但在裂解槽深度为0.5~0.6 mm时,张角在10°~25°的较小范围内变化。     

高温再热器管失效分析

某发电厂高温再热器管，材料为1Cr18Ni12Ti奥氏体不锈钢，设计使用温度545℃，运动压力13.7MPa，已使用二十多年。本次例行大修，对钢管材料进行的拉力试验结果显示材料的延伸率严重下降。为了判明材料脆化的原因及对设备安全运动的影响，本工作采用SEM等对从高温再热器截取的试样进行了断口和微观组织的分析。     

An analysis of piecewise homogeneous dielectric rod antennas

The radiation characteristic of piecewise homogeneous dielectric rod antennas is studied by using the volume equivalence principle. Experimental results are presented for comparison.     

20万kW发电机线圈的失效分析

某发电总厂苏制20万kW发电机机组转子线圈，在运行20年后发生裂纹。我们采用扫描电镜观察，结合能谱成分分析和金相观察，对发电机机组线圈的裂纹进行了全面的分析，根据分析结果总结了裂纹产生的原因，为机组的安全运行提供了科学的依据。     

贴片电容器失效分析

采用外观检查、金相切片、SEM和EDS分析等手段,通过对贴片电容器失效实例的分析,介绍了对贴片电容器失效的分析过程与方法,得出了内部电极间的陶瓷介质裂纹存在并联电阻特性,这是导致电容器产生漏电失效的主要原因,该裂纹属制造缺陷。失效分析对贴片电容器制造工艺有质量控制作用。     

Sensitivity analysis of TWT's small signal gain based on the effectof rod shape and dimensions

An extensive study aiming at analyzing the effect of rod shapes and dimensions on the gain of helix traveling wave tubes (TWTs) is performed. The evaluation of tube small-signal gain is obtained by making use of a rigorous field analysis which takes into account the helix tape model and the dielectric inhomogeneous loading conditions. Computing time to perform the analysis is extremely low compared with the time required in the case of a full wave, three-dimensional (3-D) electromagnetic simulator. The accuracy of the simulation approach has been extensively verified in a previous paper. A novel expression for the attenuation constant has been introduced in the model to improve the quality of results. The proposed study allows a better understanding of tube behavior before fabrication highlighting the contribution of the shape, the mechanical tolerances and the ϵ_r variation of the rods to the small-signal gain