Nanometer grain boundary sliding in Cu: [011] symmetric tilt boundaries, misorientation dependence and anisotropy

1990 ◽  
Vol 38 (12) ◽  
pp. 2553-2560 ◽  
Author(s):  
R. Monzen ◽  
Y. Sumi ◽  
K. Kitagawa ◽  
T. Mori
2003 ◽  
Vol 778 ◽  
Author(s):  
Katsuyuki Matsunaga ◽  
Hitoshi Nishimura ◽  
Hiroyuki Muto ◽  
Takahisa Yamamoto ◽  
Yuichi Ikuhara

AbstractBicrystal experiments were performed to investigate atomic structures and high-temperature creep properties of [0001] symmetric tilt grain boundaries in Al2O3. Al2O3 bicrystals with Σ7, Σ31 and Σ39 boundaries were fabricated by a diffusion bonding technique, and their atomic arrangements at the grain boundary cores were analyzed by high-resolution transmission electron microscopy (HRTEM), in combination with static lattice calculations based on two-body ionic potentials. Compressive creep tests were also conducted to examine the behavior of grain boundary sliding for the above bicrystals. It was found that the behavior of grain boundary sliding depends on the grain boundary characters, whereas the trend of grain boundary sliding was not related to their Σ values. In contrast, HRTEM observations showed that the Σ31 boundary exhibiting the highest sliding rate has open spaces at the boundary core. Since grain boundary diffusion is expected to accommodate strains at grain boundary cores during sliding, it is likely that such open spaces give rise to high diffusivity at the grain boundary core, which results in the rapid grain boundary sliding of Σ31.


2002 ◽  
Vol 43 (7) ◽  
pp. 1561-1565 ◽  
Author(s):  
Tsuyoshi Watanabe ◽  
Hidehiro Yoshida ◽  
Yuichi Ikuhara ◽  
Taketo Sakuma ◽  
Hiroyuki Muto ◽  
...  

Author(s):  
Nancy J. Tighe

Silicon nitride is one of the ceramic materials being considered for the components in gas turbine engines which will be exposed to temperatures of 1000 to 1400°C. Test specimens from hot-pressed billets exhibit flexural strengths of approximately 50 MN/m2 at 1000°C. However, the strength degrades rapidly to less than 20 MN/m2 at 1400°C. The strength degradition is attributed to subcritical crack growth phenomena evidenced by a stress rate dependence of the flexural strength and the stress intensity factor. This phenomena is termed slow crack growth and is associated with the onset of plastic deformation at the crack tip. Lange attributed the subcritical crack growth tb a glassy silicate grain boundary phase which decreased in viscosity with increased temperature and permitted a form of grain boundary sliding to occur.


1983 ◽  
Vol 44 (C9) ◽  
pp. C9-759-C9-764
Author(s):  
E. Bonetti ◽  
A. Cavallini ◽  
E. Evangelista ◽  
P. Gondi

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