On the influence of crystallography on creep of circular notched single crystal superalloy specimens

被引：8
作者：
Cao, L. [1 ]
Thome, P. [1 ]
Jacome, L. Agudo [2 ]
Somsen, C. [1 ]
Cailletaud, G. [3 ]
Eggeler, G. [1 ]
机构：
[1] Ruhr Univ Bochum, Inst Werkstoffe, Univ Str 150, D-44801 Bochum, Germany
[2] Bundesanstalt Mat Forsch & Prufung BAM, Abt Werkstofftech, Unter Eichen 87, D-12205 Berlin, Germany
[3] PSL Res Univ, Mines Paristech, Ctr Mat, CNRS,UMR 7633, 63-65 Rue Henri Auguste Desbrueres, F-91003 Evry, France
来源：
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING | 2020年 / 782卷
关键词：
Single crystal Ni-Base superalloys; Double notched creep specimen; Stress distribution; Lattice rotation; Cracks; Fracture; STRESS STATE; MULTIAXIAL CREEP; STRUCTURAL CALCULATIONS; HIGH-TEMPERATURE; RUPTURE; MICROSTRUCTURE; DAMAGE; REDISTRIBUTION; MECHANISMS; NUCLEATION;
D O I：
10.1016/j.msea.2020.139255
中图分类号：
TB3 [工程材料学];
学科分类号：
0805 ; 080502 ;
摘要：
The present work contributes to a better understanding of the effect of stress multiaxiality on the creep behavior of single crystal Ni-base superalloys. For this purpose we studied the creep deformation and rupture behavior of double notched miniature creep tensile specimens loaded in three crystallographic directions [100], [110] and [111] (creep conditions: 950 degrees C and 400 MPa net section stress). Crystal plasticity finite element method (CPFEM) was used to analyze the creep stress and strain distributions during creep. Double notched specimens have the advantage that when one notch fails, the other is still intact and allows to study a material state which is close to rupture. No notch root cracking was observed, while microstructural damage (pores and micro cracks) were frequently observed in the center of the notch root region. This is in agreement with the FEM results (high axial stress and high hydrostatic stress in the center of the notched specimen). Twinning was observed in the notch regions of [110] and [111] specimens, and < 112 > {111} twins were detected and analyzed using orientation imaging scanning electron microscopy. The present work shows that high lattice rotations can be detected in SXs after creep fracture, but they are associated with the high strains accumulated in the final rupture event.
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页数：13
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