Double minimum creep of single crystal Ni-base superalloys
Double minimum creep of single crystal Ni-base superalloys
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DOI：
10.1016/j.actamat.2016.04.012
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发表时间：
2016-06
期刊：
影响因子：
9.4
通讯作者：
X. Wu;P. Wollgramm;C. Somsen;A. Dlouhý;A. Kostka;G. Eggeler
中科院分区：
文献类型：
--
作者：
X. Wu;P. Wollgramm;C. Somsen;A. Dlouhý;A. Kostka;G. Eggeler
单晶高温合金ERBO/1拉伸试样的低温（750 °C）和高应力（800 MPa）蠕变曲线在加载<001>方向上显示出两个蠕变速率极小值。应变速率在0.1%应变下（30分钟后达到）朝向第一个尖锐的局部蠕变速率最小值降低。然后，变形速率增加，并在1%时达到中间最大值（1.5 h后达到）。随后，应变率下降到全球最低值为5%（260小时），三级蠕变（不考虑在本工作）导致最终破裂之前。我们将联合收割机高分辨率微型蠕变测试与衍射对比透射电子显微镜相结合，并确定了控制这种双最小类型蠕变行为的基本过程。我们提供了新的定量信息，在低温和高应力蠕变过程中的微观结构的演变，重点是γ通道位错活动和层错剪切的γ′相。我们讨论了我们的结果，在文献中发表的以前的工作，并强调需要进一步工作的领域。
Low temperature (750 °C) and high stress (800 MPa) creep curves of single crystal superalloy ERBO/1 tensile specimens loaded in the <001> direction show two creep rate minima. Strain rates decrease towards a first sharp local creep rate minimum at 0.1% strain (reached after 30 min). Then deformation rates increase and reach an intermediate maximum at 1% (reached after 1.5 h). Subsequently, strain rates decrease towards a global minimum at 5% (260 h), before tertiary creep (not considered in the present work) leads to final rupture. We combine high resolution miniature creep testing with diffraction contrast transmission electron microscopy and identify elementary processes which govern this double-minimum type of creep behavior. We provide new quantitative information on the evolution of microstructure during low temperature and high stress creep, focusing on γ-channel dislocation activity and stacking fault shear of the γ′-phase. We discuss our results in the light of previous work published in the literature and highlight areas in need of further work.