Grain growth and the lifetime of diffusion creep deformation

2011 ◽  
Vol 360 (1) ◽  
pp. 257-272 ◽  
Author(s):  
Mark A. Pearce ◽  
John Wheeler
Keyword(s):  
Grain Growth ◽  
Creep Deformation ◽  
Diffusion Creep

scholarly journals Creep deformation behavior during densification of ZrB2-SiBCN ceramics with ZrO2 additive

2020 ◽  
Vol 9 (5) ◽  
pp. 544-557
Author(s):  
Bo Feng ◽  
Zhenhang Wang ◽  
Yunhao Fan ◽  
Jinghua Gu ◽  
Yue Zhang
Keyword(s):  
Grain Boundary ◽  
Creep Deformation ◽  
Applied Pressure ◽  
Grain Boundary Sliding ◽  
Diffusion Creep ◽  
Atom Diffusion ◽  
Grain Boundary Mobility ◽  
Controlling Mechanism ◽  
Temperature Ranges ◽  
Lower Temperature

Abstract ZrB2-SiBCN ceramics with ZrO2 additive are hot-pressed under a constant applied pressure. The densification behavior of the composites is studied in a view of creep deformation by means of the Bernard-Granger and Guizard model. With determination of the stress exponent (n) and the apparent activation energy (Qd), the specific deformation mechanisms controlling densification are supposed. Within lower temperature ranges of 1300–1400 °C, the operative mechanism is considered to be grain boundary sliding accommodated by atom diffusion of the polymer-derived SiBCN (n = 1, Qd = 123±5 kJ/mol) and by viscous flow of the amorphous SiBCN (n = 2, Qd = 249±5 kJ/mol). At higher temperatures, the controlling mechanism transforms to lattice or intra-granular diffusion creep (n = 3–5) due to gradual consumption of the amorphous phase. It is suggested that diffusion of oxygen ions inside ZrO2 into the amorphous SiBCN decreases the viscosity, modifies the fluidity, and contributes to the grain boundary mobility.

Diffusion Creep during Grain Growth in Nanocrystalline Metals

2004 ◽  
Vol 467-470 ◽  
pp. 1283-1288
Author(s):  
Yuri Estrin ◽  
Günter Gottstein ◽  
Lasar S. Shvindlerman
Keyword(s):  
Grain Size ◽  
Creep Rate ◽  
Grain Growth ◽  
Diffusion Creep ◽  
Secondary Creep ◽  
Rate Reduction ◽  
Vacancy Generation ◽  
Diffusion Controlled ◽  
Initial Stage ◽  
Rate Behaviour

Diffusion controlled creep in nanostructured materials is considered for the case when grain growth occurs concurrently. The Nabarro-Herring and Coble mechanisms that would predict creep rate reduction are re-considered to include the effect of grain-growth induced vacancy generation. It is shown that under such conditions creep is accelerated during an initial stage of grain growth as compared to the case of constant grain size. This creep enhancement stage is followed by a period of reduced creep rate. The predicted strain rate behaviour resembles primary and secondary creep.

Relationship Between The Void And Hillock Formation And The Grain Growth In Thin Aluminum Films

1996 ◽  
Vol 428 ◽  
Author(s):  
O. V. Kononenko ◽  
V. N. Matveev
Keyword(s):  
Stress Relaxation ◽  
Grain Growth ◽  
The Self ◽  
Diffusion Creep ◽  
Silicon Substrates ◽  
Aluminum Films ◽  
Bias Stress ◽  
Transmission Electron ◽  
Thin Aluminum ◽  
Hillock Formation

AbstractVoid and hillock formation during annealing was studied depending on the deposition conditions. Aluminum films were deposited onto oxidized silicon substrates by the self-ion assisted technique. The bias 0 or 6 kV was applied to the substrate during deposition. The films were then annealed in vacuum for 1 hour in the temperature range from 1500 to 550°C. The structure of the films was investigated by transmission electron microscopy.It was found that recrystallization and void and hillock formation in the films depend on the bias during deposition. Normal grain growth occurred in the films deposited without bias. Abnormal grain growth was observed in the 6 kV-films. It was also found that the mechanism of stress relaxation during thermal cycling depends on the self-ion bombardment. In the films prepared without bias, stress relaxation proceeds by diffusion creep. In the films deposited at the 6 kV bias, stress relaxation proceeds by plastic deformation.

Effects of grain growth on grain-boundary diffusion creep by molecular-dynamics simulation

2004 ◽  
Vol 52 (7) ◽  
pp. 1971-1987 ◽  
Author(s):  
A.J. Haslam ◽  
V. Yamakov ◽  
D. Moldovan ◽  
D. Wolf ◽  
S.R. Phillpot ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Grain Boundary ◽  
Grain Growth ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Dynamics Simulation ◽  
Diffusion Creep
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