Unveiling the Re effect in Ni-based single crystal superalloys

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...

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Bibliographic Details
Published in:Nature communications 2020-01, Vol.11 (1), p.389-389, Article 389
Main Authors: Wu, Xiaoxiang, Makineni, Surendra Kumar, Liebscher, Christian H., Dehm, Gerhard, Rezaei Mianroodi, Jaber, Shanthraj, Pratheek, Svendsen, Bob, Bürger, David, Eggeler, Gunther, Raabe, Dierk, Gault, Baptiste
Format: Article
Language:English
Subjects:
147/143
639/301/1023/1026
639/301/1023/303
Carbon dioxide
Carbon dioxide emissions
Creep strength
Crystal defects
Dislocations
Electric power generation
Enrichment
Gas turbine engines
Gas turbines
High temperature
Humanities and Social Sciences
Image resolution
Modelling
multidisciplinary
Nickel
Nickel base alloys
Oxidation
Oxidation resistance
Power plants
Rhenium
Science
Science (multidisciplinary)
Single crystals
Strain rate
Superalloys
Thermal stability
Transmission electron microscopy
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Summary: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 CO 2 emissions in air-traffic. Adding minute amounts of rhenium to Ni-based single crystal superalloys extends their high temperature performance in engines, but the reasons behind that are still unclear. Here, the authors combine high resolution imaging and modelling to show that rhenium enriches and slows down partial dislocations to improve creep performance.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-019-14062-9