scholarly journals Model of fracture micro mechanism of Cu-Cr-Zr system by in-situ tensile test in SEM

2003 ◽  
Vol 39 (3-4) ◽  
pp. 499-507 ◽  
Author(s):  
M. Besterci ◽  
J. Ivan ◽  
P. Kulu ◽  
D. Arensburger ◽  
O. Velgosova

In the present work fracture mechanism of the Cu-Cr-Zr system was studied by "in-situ tensile test in SEM". It has been shown, that during tensile strain over the critical deformation the first cracks appeared due to the decohesion of matrix - large Cr particles interphase or by Cr particles failure. The further stress increase causes the cracks formation on matrix small Cr particles interfaces and in the clusters of Cu5Zr intermetalics. The trajectory affinal fracture was formed preferably by coalescence of cracks oriented about 67? to the loading direction. The model, presenting fracture mechanism in the investigated system was suggested.

2016 ◽  
Vol 129 (1) ◽  
pp. 138-141 ◽  
Author(s):  
M. Besterci ◽  
Š. Nagy ◽  
S.J. Huang ◽  
O. Velgosová ◽  
K. Sülleiová ◽  
...  

2021 ◽  
pp. 111180
Author(s):  
Keli Liu ◽  
Junsheng Wang ◽  
Bing Wang ◽  
Pengcheng Mao ◽  
Yanhong Yang ◽  
...  

Crystals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1047
Author(s):  
Wenxiang Jiang ◽  
Xiaoyi Ren ◽  
Jinghao Zhao ◽  
Jianli Zhou ◽  
Jinyao Ma ◽  
...  

An in situ scanning electron microscope (SEM) tensile test for Ni-based single-crystal superalloy was carried out at 1000 °C. The stress displacement was obtained, and the yield strength and tensile strength of the superalloy were 699 MPa and 826 MPa, respectively. The crack propagation process, consisting of Model I crack and crystallographic shearing crack, was determined. More interestingly, the crack propagation path and rate affected by eutectics was directly observed and counted. Results show that the coalescence of the primary crack and second microcrack at the interface of a γ/γ′ matrix and eutectics would make the crack propagation rate increase from 0.3 μm/s to 0.4 μm/s. On the other hand, crack deflection decreased the rate to 0.05 μm/s. Moreover, movement of dislocations in front of the crack was also analyzed to explain the different crack propagation behavior in the superalloy.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jung Gi Kim ◽  
Jae Wung Bae ◽  
Jeong Min Park ◽  
Wanchuck Woo ◽  
Stefanus Harjo ◽  
...  

Metals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 126 ◽  
Author(s):  
Jiabin Hou ◽  
Lin Gao ◽  
Guorong Cui ◽  
Wenzhen Chen ◽  
Wencong Zhang ◽  
...  

In situ synthesized TiB whiskers (TiBw) reinforced Ti-15Mo-3Al-2.7Nb-0.2Si alloys were successfully manufactured by pre-sintering and canned hot extrusion via adding TiB2 powders. During pre-sintering, most TiB2 were reacted with Ti atoms to produce TiB. During extrusion, the continuous dynamic recrystallization (CDRX) of β grains was promoted with the rotation of TiBw, and CDRXed grains were strongly inhibited by TiBw with hindering dislocation motion. Eventually, the grain sizes of composites decreased obviously. Furthermore, the stress transmitted from the matrix to TiBw for strengthening in a tensile test, besides grain refinement. Meanwhile, the fractured TiBw and microcracks around them contributed to fracturing.


Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1007
Author(s):  
Hao Yang ◽  
Jishen Jiang ◽  
Zhuozheng Wang ◽  
Xianfeng Ma ◽  
Jiajun Tu ◽  
...  

The fatigue fracture mechanism of a nickel-based single crystal (NBSC) superalloy with recrystallized grains was studied at 550 °C by in situ observation with a scanning electron microscope (SEM) for the first time. Multiple crack initiations associated with recrystallized grain boundaries and carbides were observed. By analysis of the slip traces and crack propagation planes, the operated slip systems were identified to be octahedral for both single crystal substrate and recrystallized grains. Distinct crystallographic fractures dominated, accompanied by recrystallized grain boundary associated crack initiations. This is different from the widely reported solely intergranular cracking at high temperature. Fatigue crack growth rate curves showed evident fluctuation, due to the interaction of fatigue cracks with local microstructures and the crack coalescence mechanism. Both the recrystallized grains and the competition between different slip systems were responsible for the deceleration and acceleration of fatigue microstructurally small crack behavior.


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