镍基单晶超合金的剪切强度研究

通过设计滑移系直接受分切应力的剪切试样形式,对镍基单晶超合金在７００℃、８５０℃和９５０℃时的瞬时剪切强度和剪切蠕变性能进行了研究。试验结果表明,本研究试样形式可以直接测量单滑移系的滑移规律,未发现晶体取向相关性。通过转换公式,瞬时剪切强度与圆棒试验结果相吻合。应用扫描电镜（ＳＥＭ）对试样断口分析表明,断口由平整的小刻面组成,从而进一步验证本试验的有效性,同时发现,由夹杂形成的空洞和平行受载方向的     

基于模糊分布参数的元件和结构系统的可靠性度量指标分析

在元件强度和外载的分布参数未知的情况下,本文提出了利用已有试验和专家经验采用模糊数对这些未知参数进行了定量描述,并给出基于可靠度指标和基于失效概率的两种元件的可靠性度量指标估计方法。比较这两种指标的结果表明,对于正态型的分布和隶属函数,基于失效概率的元件可靠性度量指标更能反映参数模糊性对元件的安全程度的影响。本文提出了方法还可以推广应用于结构系统,从而给出结构系统诸分布参数为模糊数时的可靠性度量指     

Determination of reduced Young＇s modulus of thin films using indentation test

The flat cylindrical indentation tests with different sizes of punch radius were investigated using finite element method (FEM) aimed to reveal the effect of punch size on the indentation behavior of the film/substrate system. Based on the FEM results analysis, two methods was proposed to separate film's reduced Young's modulus from a film/substrate system. The first method was based on a new weight function that quantifies film's and substrate's contributions to the overall mechanical properties of the film/substrate system in the flat cylindrical indentation test. The second method, a numerical approach, including fitting and extrapolation procedures was put forward. Both of the results from the two methods showed a reasonable agreement with the one input FE model. At last, the effect of maximum indentation depth and the surface micro-roughness of the thin film on the reduced Young's modulus of the film/substrate system were discussed. The methods proposed in the present study provide some new conceptions on evaluating other properties of thin films, e.g. creep, for which a flat-ended punch is also employed.     

基于神经网络的电力电能自适应测量方法

详细介绍了基于神经网络的电力电能自适应测量方法，给出系统原理图及电力电能测量误差自动校正方法；首次提出了LEA判别法，从而实现了梯度牛顿法的有效结合神经网络学习方法；采用DSP技术实现了电能实时快速测量，给出了实验结果。     

The Influence of Crystal Orientation on Vibration Characteristics of DD6 Nickel-Base Single Crystal superalloy Turbine Blade

Modeling of a nickel-base single crystal superalloy turbine blade which accounts for material orthotropy is carried out to investigate the influence of axial direction and randomness crystallographic orientation on the dynamic natural frequency. In this paper, the natural frequency of the blade is calculated by the finite element method based on the commercial software ABAQUS. The results show that the deviation of the axial directions has a significant effect on the lower frequency as well as on the higher frequency, while the randomness in crystallographic orientations has a great impact only on higher order frequency. It is necessary to take the crystal orientation into account as an optimized factor and the variation of the vibration characteristics can be predicted.     

电溶法再生WC在凿岩柱齿合金生产中的应用

通过选择合适的电溶法再生WC,合理设计牌号,严格控制生产过程,可以生产出较高质量的钎头用柱齿合金。     

等离激元共振增强多晶硅薄膜太阳电池性能研究

采用磁控溅射方法,在多晶硅薄膜太阳电池表面沉积了不同粒径大小的Au纳米粒子,利用粒径大小可调控的Au纳米粒子的局域表面等离激元共振增强效应(LSPR),对入射光中的可见光区域实现“光俘获”;采用UV-vis吸收光谱对LSPR进行了研究,结果表明,LSPR能够有效拓展Au纳米粒子的光谱响应范围(400～800 nm),并且,随着Au纳米粒子粒径的增大,LSPR共振吸收峰呈现出明显“红移”;同时,通过SERS表征,证实LSPR能够有效增强Au纳米粒子周围的局域电磁场强度;最后,多晶硅太阳电池的J-V特性曲线表明,当Au纳米粒子溅射时间为50 s时,多晶硅太阳电池光电转换效率(η)最高为14.8％,比未修饰Au纳米粒子的电池η提高了42.3％.     

热处理对金属基短纤维复合材料蠕变性能影响的试验和理论研究

采用试验和有限元方法研究了热处理制度对金属基短纤维复合材料(MMC)蠕变性能的影响，同时考虑了2种不同热处理制度和1种铸造状态。试验结果表明，MMC的蠕变响应与热处理制度有关。在相同蠕变应力时，铸态试样有最小的最小蠕变应变率和最长的蠕变寿命，而热处理制度2(试样在550℃保温24h后随炉冷却)具有明显的最大的最小蠕变应变率和最短蠕变寿命，热处理制度1(试样在550℃保温24h后水冷)具有中等的最小蠕变应变率和中等的蠕变寿命。用单胞模型结合有限元方法模拟分析了热处理的影响，结果表明，热处理制度的影响可以归于热处理引起的残余应力和残余应变以及它们的历史，具体可以归于基体的蠕变耗散能、纤维轴向力和纤维—基体界面力。同时考虑了单胞模型的参数对上述分析结果的影响。     

镍基单晶超合金中孔洞长大的试验和有限元分析

在高温状态下，镍基单晶超合金的变形、损伤及断裂分析中，孔洞的长大都起着主要的作用。本研究进行了系列的蠕变、疲劳及热机械疲劳（TMF）试验。对试件的断面进行的SEM观察表明，所有的断面都是有许多小断面构成，在断面的中心，至少有一个孔洞。孔洞的尺寸与加载的条件相关。使用晶体塑性有限元程序对单胞模型进行分析，模拟孔洞的长大规律。给出了蠕变和弹塑性两种条件下的模拟结果及不同的晶体取向对孔穴长大的影响结果。对孔洞长大的有限元分析有助于对实验结果的理解。