Unveiling the Re effect in Ni-based single crystal superalloys.,Nature Communications

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Unveiling the Re effect in Ni-based single crystal superalloys.
Nature Communications ( IF 14.7 ) Pub Date : 2020-01-20 , DOI: 10.1038/s41467-019-14062-9
Xiaoxiang Wu ₁ , Surendra Kumar Makineni ₁ , Christian H Liebscher ₁ , Gerhard Dehm ₁ , Jaber Rezaei Mianroodi _{1,

2} , Pratheek Shanthraj _{1,

3} , Bob Svendsen _{1,

2} , David Bürger ₄ , Gunther Eggeler ₄ , Dierk Raabe ₁ , Baptiste Gault _{1,

5}

Affiliation

Single crystal Ni-based superalloys have long been an essential material for gas turbines in aero engines and power plants due to their outstanding high temperature creep, fatigue and oxidation resistance. A turning point was the addition of only 3 wt.% Re in the second generation of single crystal Ni-based superalloys which almost doubled the creep lifetime. Despite the significance of this improvement, the mechanisms underlying the so-called "Re effect" have remained controversial. Here, we provide direct evidence of Re enrichment to crystalline defects formed during creep deformation, using combined transmission electron microscopy, atom probe tomography and phase field modelling. We reveal that Re enriches to partial dislocations and imposes a drag effect on dislocation movement, thus reducing the creep strain rate and thereby improving creep properties. These insights can guide design of better superalloys, a quest which is key to reducing CO2 emissions in air-traffic.

中文翻译：

在镍基单晶高温合金中展现出Re效应。

长期以来，单晶镍基高温合金由于其出色的高温蠕变，耐疲劳性和抗氧化性，一直是航空发动机和发电厂燃气轮机的重要材料。转折点是在第二代单晶镍基高温合金中仅添加了3 wt。％的Re，这使蠕变寿命几乎翻了一番。尽管这种改进具有重要意义，但所谓的“再效应”的潜在机制仍存在争议。在这里，我们使用结合的透射电子显微镜，原子探针层析成像和相场建模，为蠕变变形过程中形成的晶体缺陷提供了Re富集的直接证据。我们发现Re会富集到部分位错，并对位错运动产生阻力作用，因此降低了蠕变应变率，从而改善了蠕变性能。这些见解可以指导设计更好的高温合金，这是减少空中交通中二氧化碳排放量的关键。

更新日期：2020-01-22

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