脆性材料的亚临界裂纹扩展和双向应力的影响

分析了陶瓷,玻璃等脆性材料的断裂机理和表征.指出了脆性材料的失效过程的三种不同的裂纹发展模式.实验研究了玻璃在静载下的亚临界裂纹扩展特征及其受双向应力的影响.从而为脆性材料的可靠性和寿命评价提供理论基础和手段.     

脆性材料粉碎机理的分形研究

应用分形几何理论，研究了脆性材料冲击粉碎方式下形成颗粒 度分布特征，发现在双对数坐标下，颗粒粒径的质量累百分含量与粒径之间直线关系，表明共粒度分布具有分表结构，上线的斜率ｂ，由公式Ｄ＝３－ｂ可求得相应的分维。分维可作为找描述粒度分布特征的一个序参量，其值反映了分布的离散趋势和颗粒的均匀程度，并在量度材料强度和估测颗粒级配等方面有重要意义。     

脆性材料强度统计分析中Weibull模数估计的试样数量的优化

为了全面的评价脆性材料强度特性指标,研究了强度统计方法中Weibull模数估计的试样数的优化问题。文中利用无偏极大似然估计理论结果,用置信度和相对误差双参数,计算出Weibull模数估计中的最优试样数,以便在Weibull模数估计试验中根据研究对象的要求,正确选用试样数量。文中结果在脆性材料强度特性评价与可靠性评价及其它适合Weibull统计的对象均可应用。     

浅谈陶瓷脆性与改善脆性的途径

主要分析了陶瓷材料的脆性特征及显微结构与脆性的关系,提出了改善脆性的途径。     

热壁加氢反应器的选材及材料的回火脆性

文章结合抚顺石油二厂精制加氢反应器的设计,就热壁加氢反应器的选材、材料的回火 脆必的表现形式、评价标准及影响因素进行了探讨,并对控制回火脆性敏感性的措施进行了总结。结果认为２．２５Ｃｒ－１Ｍｏ钢中硅含量对回火脆性敏感性有很大的影响,应注意对硅含量的控制。     

调节冷却制度降低玻化砖脆性

本文从调节窑炉冷却制度出发，提出了解决砖发脆，强度低的方法，并针对冷却制度对砖微裂纹的形成与扩展进行了初步分析讨论。     

泥页岩储层岩石力学特性及其脆性评价

本文主要就泥页岩储层岩力学实验的方式方法和过程,以及进行岩石脆性评价的计算方式等方面进行探讨,希望能够对相关工作的进行有一定的积极作用。     

关于环境材料及其评价方法的研究

对环境材料的定义、评价方法及其主要研究方向进行了初步探讨。详细研究了环境材料的功能性，经济性和环境协调性评价方法及其评价指标。结合环境材料的定义提出了评价环境材料的综合判据表达式。所得结论对于材料科学研究和材料工业技术进步具有一定的理论和实际意义。     

硬质泡沫塑料脆性性能的评价方法

硬质泡沫塑料的脆性主要采用滚动磨损试验的方法进行评价。通过测定其材料的质量磨损率,定量地分析材料的抗磨损、磨蚀、断裂等综合耐用性能,反映材料的韧性程度。根据国外大量文献报导,ASTM C421已被广泛采用作为测定硬质泡沫塑料脆性性能的方法。江苏省化工研究所根据轻工部<88>轻塑标字第七号文和<88>轻科字第八号文下     

Factors Controlling the Fracture Resistance of Brittle Cellular Materials

Previous work on brittle cellular solids has indicated that the fracture toughness may be independent of cell size. The results showed agreement with two theoretical approaches proposed by Maiti et al. to predict the toughness of porous cellular solids. One approach indicates a strut strength and cell size dependence of the bulk material toughness, whereas the other depends only on the toughness of the solid portion. The present work attempted to experimentally discern between the two approaches and identify the controlling parameters governing the mechanical behavior. Reticulated vitreous carbon samples were oxidized to introduce surface flaws into the struts. The toughness and compressive strength of the bulk material were measured before and after oxidation. Fractographic analysis of the fracture surface of individual struts was essential in being able to estimate the strut strength. It was concluded that it is the strut strength which controls the strength and toughness of the bulk cellular solid.     

Strength and Stiffness of Porous Materials

A contribution is given to the theoretical research on nondestructive testing of porous materials like ceramics, for example. Relations (so-called modulus of elasticity-modulus of rupture relations) are developed between stiffness and strength considering the material-specific pore geometry. The results presented on strength can be given a form similar to the well-known empirical Ryshkewitch formula. This means that the "constant" in this expression can be related to porosity and pore geometry such that consistency is respected between strength and elasticity.     

Nanoindentation Method for Measuring Residual Stress in Brittle Materials

The lowered threshold load for cracking with the cube-corner indenter has been used in developing a method that can be used to measure residual stresses in small volume brittle materials. By studying a series of orthogonal cracks generated at loads not exceeding 10 mN with the cube-corner indenter, a variation of crack length with position around a large Vickers impression in soda–lime glass was observed. Using an indentation fracture mechanics approach residual stresses were evaluated at the positions where the cube-corner indents had been made. The stress values thus evaluated were generally higher than those reported in the literature where micro-Vickers indents had been used to measure the stresses. Possible reasons for the disparity are discussed.     

Statistics of Flaw Interaction in Brittle Materials

The problem of elastic interaction of an array of microcracks is considered. The solution is based on an efficient surface integral method using distribution of edge dislocations to represent the microcracks in the mathematical model. From the analysis of the interaction between two identical cracks, it is seen that interaction is most likely to produce a slight enhancement in the stress intensity factor. By performing computer experiments on a random array of microcracks, the effect of crack interaction is studied statistically as a function of the density of the microcracks. The significance of the interaction effects for fracture in ceramics is discussed.     

Effect of Tangential Loading on Critical Conditions for Radial Cracking in Brittle Coatings

Results of Hertzian contact tests investigating the effects of superposed tangential loads on the critical conditions for radial cracking at the undersurfaces of brittle coatings on compliant substrates are reported. It is demonstrated that these effects are secondary, so that conventional normal indentation remains an appropriate test procedure for characterizing this highly deleterious mode of coating fracture under a wide range of complex loading conditions.     

微胶囊化相变材料的制备与评价方法

微胶囊化相变材料(MCPCM)是将微胶囊技术应用于相变材料而形成的新型复合材料,具有广阔的应用前景,现已成为相变材料应用研究领域的热点。该文综述了MCPCM的4种主要制备方法——原位聚合法、界面聚合法、凝聚法和喷雾干燥法的原理及国内外研究情况。总结了MCPCM的评价方法,将文献中常见的评价指标分成了两类,即"与制备有关的评价指标"和"与应用有关的评价指标",并介绍了相应的表征手段。指出了MCPCM在选材、制备及评价等方面存在的问题和今后的研究方向。     

《材料现代测试方法》的教学探索

《材料现代测试方法》课程是材料化学专业的一门重要的专业基础课,通过课程建设的具体实施和教学实践,发展改革其课程教学内容,优化了课堂教学方法和手段,提高了教学效果,并介绍了案例教学法在《材料现代测试方法》课程中的应用,理论联系实际,培养了学生的动手能力和思考能力。同时对实验教学内容进行设计,加入开放性实验,激发学生兴趣。     

工程陶瓷的断裂特性与评价

综述了陶瓷材料的强度与断裂理论的现状、发展及问题,讨论了脆性陶瓷失效研究的几个主要方面及相应的技术。     

塑料材料生物降解性评价方法的研究进展

综述了近年来国内外塑料材料生物降解性的评价标准和测试方法,通过综合分类与比较,指出了生物降解性测试方法的优缺点,并介绍了目前国际上较有影响力的生物降解材料的可堆肥认证机构。