Measurement of the effective γ/γ′ lattice mismatch during high temperature creep of Ni-based single crystal superalloy
Measurement of the effective γ/γ′ lattice mismatch during high temperature creep of Ni-based single crystal superalloy
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DOI：
10.1016/j.matchar.2012.12.003
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发表时间：
2013-03-01
影响因子：
4.7
通讯作者：
Bastie, Pierre
中科院分区：
文献类型：
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作者：
Dirand, Laura;Cormier, Jonathan;Bastie, Pierre
高温有效已经使用三种不同的技术在宽温度范围[930 ℃-1125 ℃]内测量了Ni基单晶超合金的（受约束的）γ/γ ′晶格失配：同步辐射下的原位X射线衍射，使用透射电子显微镜（TEM）测量和事后γ/γ '界面位错网络网格尺寸或高分辨率扫描电子显微镜（SEM）。结果表明，所有三种技术是互补的，考虑精度和空间分布的晶格失配在分析的体积，它们提供了一个非常相似的平均值的伽玛/伽玛'晶格失配。由于等温蠕变实验是在可变的外加应力下进行的，因此可以推断，使用TEM和SEM的死后晶格失配测量代表了实验的最后一个加载步骤，即使位错网络处于平衡构型之外。与无约束的γ/γ '晶格失配相反，有效晶格失配是温度、外加应力和累积塑性应变的函数，即是样品热机械历史的函数。(C)2012爱思唯尔公司出版
The high temperature effective (constrained) gamma/gamma' lattice mismatch of a Ni-based single crystal superalloy has been measured in a wide temperature range [930 degrees C-1125 degrees C] using three different techniques: in-situ X-ray diffraction under synchrotron radiation, and post-mortem gamma/gamma' interfacial dislocation network mesh size measurements using Transmission Electron Microscopy (TEM) or high resolution Scanning Electron Microscopy (SEM). It is shown that all three techniques are complementary considering precision and spatial distribution of lattice mismatches in the analyzed volume and that they provide a very similar average value of the gamma/gamma' lattice mismatch. Since isothermal creep experiments were performed under variable applied stress, it is deduced that the post-mortem lattice misfit measurements using both TEM and SEM are representative of the very last loading step of the experiments, even if dislocation networks are out of an equilibrium configuration. Contrary to the unconstrained gamma/gamma' lattice mismatch, it is shown that the effective lattice mismatch is a function of the temperature, applied stress and accumulated plastic strain, i.e. of the thermomechanical histories of the samples. (C) 2012 Published by Elsevier Inc.