On the Temperature Limits of Ni-Based Superalloys

被引：4
作者：
Barba, Daniel [1 ,2 ]
Egan, Ashton [4 ]
Kench, Steve [1 ]
Smith, Tim M. [5 ]
Mills, Michael J. [4 ]
Reed, Roger C. [1 ,3 ]
机构：
[1] Univ Oxford, Dept Mat, Parks Rd, Oxford OX1 3PH, England
[2] Univ Politecn Madrid, Dept Aerosp Mat, ETSIAE, Madrid 28040, Spain
[3] Univ Oxford, Dept Engn Sci, Parks Rd, Oxford OX1 3PJ, England
[4] Ohio State Univ, Dept Mat Sci, Columbus, OH 43210 USA
[5] NASA, Glenn Res Ctr, 21000 Brookpk Rd, Cleveland, OH 44135 USA
来源：
TMS 2020 149TH ANNUAL MEETING & EXHIBITION SUPPLEMENTAL PROCEEDINGS | 2020年
关键词：
Single crystal; Superalloys; TEM; DFT; Crystal plasticity; ALLOYING ELEMENTS; SEGREGATION; CREEP; FAULTS;
D O I：
10.1007/978-3-030-36296-6_73
中图分类号：
T [工业技术];
学科分类号：
08 ;
摘要：
The peculiar atomic structure of gamma' precipitates [Ni3(Al/Ti)-L12] in Ni-based superalloys produces high-energy faults when dislocations glide them, giving their significant strength at high temperatures. The mechanisms behind the strength failure of these alloys above 800 degrees C are still controversial. Recent advances in atomic resolution microscopy have allowed to study these mechanisms with unprecedented detail. In our study, we have characterised a SX superalloy from RT to 1000 degrees C. Multiscale microscopy (TEM and SEM) are combined with physical modelling to fully understand the correlation between the strength drop and the changes in the gamma' shearing mechanism. Our results show that, far from previous beliefs, the initial failing of alloy strength is not a consequence of dislocation climbing. Instead, local chemical changes around the gamma' shearing dislocations boost their gliding, thus producing the sudden drop of strength. This new understanding can be used to beat the current temperature limits of these alloys.
引用
收藏
页码：785 / 792
页数：8
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