Anisotropic creep damage and fracture mechanism of nickel-base single crystal superalloy under multiaxial stress

2017 ◽  
Vol 692 ◽  
pp. 301-312 ◽  
Author(s):  
Zhixun Wen ◽  
Dongxu Zhang ◽  
Songwei Li ◽  
Zhufeng Yue ◽  
Jingyun Gao
2014 ◽  
Vol 783-786 ◽  
pp. 1188-1194 ◽  
Author(s):  
Su Gui Tian ◽  
Zhong Ge Guo ◽  
De Long Shu ◽  
Jun Xie

By means of creep properties measurement and microstructure observation, an investigation has been made into the damage and fracture mechanism of a nickel-based single crystal superalloy during creep at moderate temperature. Results show that the deformation mechanism of the alloy in the latter stage of creep is that the primary-secondary slipping systems are alternately activated, and the micro-crack is firstly initiated on the γ′/γ phases interface in the intersection regions of two slip systems. As creep goes on, the micro-crack is propagated along the γ′/γ interface, which is perpendicular to stress axis, to form the square-like cleavage plane on the (001) plane. Thereinto, the propagation of the cracks on (001) plane is intersected with {111} cleavage plane which is secondly activated, which may terminate the propagation of the crack to form the cleavage plane with square-like feature on (001) plane along the <110> directions. Due to the multi-cracks may be propagated on different cross-section of the alloy during creep, and the tearing edge or secondary cleavage plane are formed along the direction with bigger shearing stress at the crack tip, which makes the multi-cracks connected each other until the occurrence of creep fracture, this is thought to be the main reason of the creep fracture having the uneven and multi-level cleavage characteristics.


2018 ◽  
Vol 147 ◽  
pp. 16-20 ◽  
Author(s):  
Min Yang ◽  
Jun Zhang ◽  
Hua Wei ◽  
Weimin Gui ◽  
Haijun Su ◽  
...  

2021 ◽  
pp. 109737
Author(s):  
Hai-Qing Pei ◽  
Meng Li ◽  
Ping Wang ◽  
Xiao-Hu Yao ◽  
Zhi-Xun Wen ◽  
...  

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 623
Author(s):  
Xiaoyan Wang ◽  
Meng Li ◽  
Yuansheng Wang ◽  
Chengjiang Zhang ◽  
Zhixun Wen

Taking nickel-based single crystal superalloy DD6 as the research object, different degrees of creep damage were prefabricated by creep interruption tests, and then the creep damage was repaired by the restoration heat treatment system of solid solution heat treatment and two-stage aging heat treatment. The results show that with the creep time increasing, the alloy underwent microstructure evolution including γ′ phase coarsening, N-type rafting and de-rafting. After the restoration heat treatment, the coarse rafted γ′ phase of creep damaged specimens dissolved, precipitated, grew up, and became cubic again. Except for the specimens with creep interruption of 100 h, the γ′ phase can basically achieve the same arrangement as the γ′ phase of the original sample. The comparison of the secondary creep test shows that the steady-state creep stage of the test piece after the restoration heat treatment is relatively increased, and the total creep life can reach the same level as the primary creep life. The high temperature creep properties of the tested alloy are basically recovered, and the restoration heat treatment effect is good.


2015 ◽  
Vol 636 ◽  
pp. 608-612 ◽  
Author(s):  
Xinhong Xiong ◽  
Dunmiao Quan ◽  
Pengdan Dai ◽  
Zhiping Wang ◽  
Qiaoxin Zhang ◽  
...  

Author(s):  
Piao Li ◽  
Wen Jiang ◽  
Shao-Shi Rui ◽  
Wei-xing Yao ◽  
Hui-ji Shi ◽  
...  

2015 ◽  
Vol 750 ◽  
pp. 139-144 ◽  
Author(s):  
De Long Shu ◽  
Su Gui Tian ◽  
Xin Ding ◽  
Jing Wu ◽  
Qiu Yang Li ◽  
...  

By means of heat treatment and creep property measurement, an investigation has made into the creep behaviors of a containing 4.5% Re nickel-base single crystal superalloy at high temperature. Results show that the elements W, Mo and Re are enriched in the dendrite arm regions, the elements Al, Ta, Cr and Co are enriched in the inter-dendrite region, and the segregation extent of the elements may be obviously reduced by means of heat treatment at high temperature. In the temperature ranges of 1070--1100 °C, the 4.5% Re single crystal nickel-based superallloy displays a better creep resistance and longer creep life. The deformation mechanism of the alloy during steady state creep is dislocations slipping in the γ matrix and climbing over the rafted γ′ phase. In the later stage of creep, the deformation mechanism of alloy is dislocations slipping in the γ matrix, and shearing into the rafted γ′ phase, which may promote the initiation and propagation of the micro-cracks at the interfaces of γ/γ′ phases up to the occurrence of creep fracture.


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