scholarly journals Creep properties and deformation mechanisms of single-crystalline γ′-strengthened superalloys in dependence of the Co/Ni ratio

Author(s):  
N. Volz ◽  
C.H. Zenk ◽  
N. Karpstein ◽  
M. Lenz ◽  
E. Spiecker ◽  
...  
1989 ◽  
Vol 170 ◽  
Author(s):  
Håkan A. Swan ◽  
Colette O'meara

AbstractPreliminary creep tests were performed on SiC whisker reinforced and matrix Si3N4 material fabricated by the NPS technique. The material was extensively crystallised in the as received material, leaving only thin amorphous films surrounding the grains. No improvement in the creep resistance could be detected for the whisker reinforced material. The deformation mechanisms were found to be that of cavitation in the form of microcracks, predominantly at the whisker/matrix interfaces, and the formation of larger cracks. Extensive oxidation of the samples, as a result of high temperature exposure to air, was observed for the materials tested at 1375°C.


2020 ◽  
Vol 186 ◽  
pp. 95-98
Author(s):  
Rolf Schaarschuch ◽  
Carl-Georg Oertel ◽  
Guanghui Cao ◽  
Jens Freudenberger ◽  
Werner Skrotzki

2016 ◽  
Vol 2016 (0) ◽  
pp. OS11-22
Author(s):  
Kosuke SHIMBARA ◽  
Toshiyuki KONDO ◽  
Hiroyuki HIRAKATA ◽  
Kohji MINOSHIMA

ACS Nano ◽  
2019 ◽  
Vol 13 (8) ◽  
pp. 9082-9090 ◽  
Author(s):  
Sheng Yin ◽  
Guangming Cheng ◽  
Gunther Richter ◽  
Huajian Gao ◽  
Yong Zhu

2013 ◽  
Vol 747-748 ◽  
pp. 672-677 ◽  
Author(s):  
Su Gui Tian ◽  
Xin Wang ◽  
Chen Liu ◽  
Wen Ru Sun

By means of creep properties measurement and microstructure observation, the influence of the traces P, B on creep behaviors and fracture mechanism of GH4169 alloy was investigated. Results showed that during creep the twinning was thought to be the main deformation mechanism of GH4169 alloy, however the deformation mechanisms of alloy containing P, B were the twinning and slipping of dislocations activated within the grains. And the fact that the slipping of dislocations activated within the grain can delay the stress concentration in the local regions to restrain the initiation of the cracks to improve the creep resistance of the alloy. Compared to GH4169 alloy, the fracture of GH4169G alloy displayed the non-smooth surface. The adding traces P, B were segregated in the region near the boundary, which may promote the particle-like δ phase precipitated along the boundary to restrain the boundaries slipping and the cracks propagation. This was thought to be the main reason for enhancing the strength of the boundary and prolonging the creep life.


2014 ◽  
Vol 1033-1034 ◽  
pp. 1213-1219
Author(s):  
Yu Xin Zhao ◽  
Ying Zhang ◽  
Yan Peng Li ◽  
Zi Feng Yan

Here, we developed single crystalline Cu@C nanowires with fivefold twinned structure via a facile hydrothermal method. In situ uniaxial tension tests of these NWs performed in transmission electron microscopy chamber reveal the ultrahigh strength (as much as 6.2 GPa) accompanied by favorable ductility (elongation>15%). The excellent performances benefit from nanoscale dimensions, unique penta-twinned geometry and good crystalline quality with protection of carbon shells. The study also provides direct experimental evidence for the theoretical modeling on the deformation mechanisms of metallic nanowires that have appeared in recent years. We expect that these findings can open a new window for applications in micro-or nanoelectromechanical devices where superior mechanical performances are desirable.


Micromachines ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 265 ◽  
Author(s):  
Pengyue Zhao ◽  
Qi Zhang ◽  
Yongbo Guo ◽  
Huan Liu ◽  
Zongquan Deng

Nanoparticle (NP), as a kind of hard-to-machine component in nanofabrication processes, dramatically affects the machined surface quality in nano-cutting. However, the surface/subsurface generation and the plastic deformation mechanisms of the workpiece still remain elusive. Here, the nano-cutting of a single-crystalline copper workpiece with a single spherical embedded nanoparticle is explored using molecular dynamics (MD) simulations. Four kinds of surface/subsurface cases of nanoparticle configuration are revealed, including being removed from the workpiece surface, moving as a part of the cutting tool, being pressed into the workpiece surface, and not interacting with the cutting tool, corresponding to four kinds of relative depth ranges between the center of the nanoparticle and the cutting tool. Significantly different plastic deformation mechanisms and machined surface qualities of the machined workpiece are also observed, suggesting that the machined surface quality could be improved by adjusting the cutting depth, which results in a change of the relative depth. In addition, the nanoparticle also significantly affects the processing forces in nano-cutting, especially when the cutting tool strongly interacts with the nanoparticle edge.


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