Microstructure and temperature dependence of intergranular strains on diffractometric macroscopic residual stress analysis
Microstructure and temperature dependence of intergranular strains on diffractometric macroscopic residual stress analysis
复制标题
DOI：
10.1016/j.msea.2014.09.033
复制
发表时间：
2014-11-17
期刊：
影响因子：
6.4
通讯作者：
Stockinger, M.
中科院分区：
文献类型：
--
作者：
Wagner, J. N.;Hofmann, M.;Stockinger, M.
当考虑到部件的安全性和制造方面时，复杂高性能合金部件中的宏观残余应力的知识是至关重要的。衍射实验是研究残余应力的重要方法之一。然而，由衍射实验确定的残余应变的一个分量，称为微观应变或晶间残余应变，发生在晶粒的长度尺度上，因此对这些分量的寿命仅起次要作用。为了可靠地测定宏观应变（这些晶间残余应变的影响最小），ISO标准建议使用特定的布拉格反射。在这里，我们比较了两种不同的沉淀硬化IN 718（INCONEL 718）样品，具有相同的化学成分的晶间应变的积累。由于晶间应变也受温度影响，因此将室温测量结果与T=550 ℃时的结果进行比较。结果表明，在T=550 ℃的测量温度下，微观结构参数（例如晶粒尺寸或沉淀物类型）对晶间应变演化的影响大于温度的影响。结果还表明，用于衍射残余应力分析的布拉格反射的选择不仅取决于其化学成分，而且取决于样品的微观结构。此外，衍射弹性常数（德克斯）的所有测得的布拉格反射。(C)2014爱思唯尔有限公司版权所有。
Knowledge of the macroscopic residual stresses in components of complex high performance alloys is crucial when it comes to considering the safety and manufacturing aspects of components. Diffraction experiments are one of the key methods for studying residual stresses. However a component of the residual strain determined by diffraction experiments, known as microstrain or intergranular residual strain, occurs over the length scale of the grains and thus plays only a minor role for the life time of such components. For the reliable determination of macroscopic strains (with the minimum influence of these intergranular residual strains), the ISO standard recommends the use of particular Bragg reflections. Here we compare the build-up of intergranular strain of two different precipitation hardened IN 718 (INCONEL 718) samples, with identical chemical composition. Since intergranular strains are also affected by temperature, results from room temperature measurement are compared to results at T=550 degrees C. It turned out that microstructural parameters, such as grain size or type of precipitates, have a larger effect on the intergranular strain evolution than the influence of temperature at the measurement temperature of T=550 degrees C. The results also show that the choice of Bragg reflections for the diffractometric residual stress analysis is dependent not only on its chemical composition, but also on the microstructure of the sample. In addition diffraction elastic constants (DECs) for all measured Bragg reflections are given. (C) 2014 Elsevier B.V. All rights reserved.