X-ray-diffraction approach for studies on fatigue and creep
X-ray-diffraction approach for studies on fatigue and creep
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用于疲劳和蠕变研究的 X 射线衍射方法
DOI：
10.1007/bf02322729
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发表时间：
1973
影响因子：
2.4
通讯作者：
S. Taira
中科院分区：
文献类型：
--
作者：
S. Taira
众所周知，x射线衍射是研究晶体材料微观结构最有力的手段之一。x射线衍射在应用于金属材料时是有利的；它对金属晶体结构的变化反应非常灵敏。x射线衍射方法的另一个特点优势是其在测量晶体材料参数时的非破坏性，使我们能够观察金属的机械现象过程，如疲劳和蠕变。在变形材料上获得的x射线衍射图包含了大量的信息，这些信息涵盖了与现有材料性质相一致的微观和宏观特征。用X射线测量的残余应力称为宏观材料参数。它是通过测量衍射剖面峰的位移来评估的。轮廓的扩散度对应于变形晶体材料微观结构的不规则性，称为亚宏观材料参数。x射线微束衍射技术提供了亚晶粒尺寸、取向偏差和微晶格应变等微观结构变化的信息。轮廓分析是评估微观材料参数的另一种方法：颗粒尺寸和微观应变。通过在材料力学行为的研究中适当地结合这些技术，可以提取控制现象的参数，以促进对其机理的讨论。本讲座介绍了用x射线衍射技术来评估材料的宏观、亚宏观和微观参数，并通过碳钢在室温和高温下的疲劳和蠕变的研究实例来证明这种方法，其中从材料参数变化的角度讨论了各种现象。研究了钢在室温下疲劳裂纹的萌生和扩展、等温和热疲劳过程中的组织变化以及变载荷下高温蠕变的组织变化。
It is well known that X-ray diffraction is one of the most powerful means for investigating the microscopic structure of crystalline materials. X-ray diffraction is advantageous when it is applied to metallic materials; it responds very sensitively to changes in the metal's crystalline structure. Another characteristic advantage of the X-ray-diffraction approach is its nondestructive nature in the measurement of crystalline-material parameters, enabling us to observe the process of mechanical phenomena of metals, such as fatigue and creep.The X-ray-diffraction patterns obtained on a deformed material include a great deal of information covering the microscopic and macroscopic characters consistent with the nature of the existing material. Residual stress measured by means of X ray is called the macroscopic-material parameter. It is evaluated by measuring the shift of the peak of a diffraction profile. The diffusiveness of the profile corresponds to the irregularity in microscopic structure of deformed crystalline material and it is noted as the submacroscopic material parameter. The X-ray-microbeam diffraction technique supplies information on the change in microscopic structure such as subgrain size, misorientation and microlattice strain. Profile analysis is another way to evaluate the microscopic-material parameters: particle size and microscopic strain.By appropriately combining these techniques in the study of mechanical behavior of materials, the parameters that control the phenomena may be extracted to facilitate discussion of their mechanism. In this lecture, X-ray-diffraction techniques to evaluate the macroscopic, submacroscopic and microscopic-material parameters are presented and the approach is demonstrated by exhibiting a case of studies on fatigue and creep of carbon steels at room and elevated temperature, where phenomena are discussed in terms of the change in the material parameters. Initiation and propagation of fatigue crack in steel at room temperature, the change in microstructure during isothermal and thermal fatigue, and also that in creep at elevated temperature under variational load are presented.