Grain Boundary Decohesion by Impurity Segregation in a Nickel-Sulfur System

Science ◽  
2005 ◽  
Vol 307 (5708) ◽  
pp. 393-397 ◽  
Author(s):  
M. Yamaguchi
2012 ◽  
Vol 85 (21) ◽  
Author(s):  
Shengjun Zhang ◽  
Oleg Y. Kontsevoi ◽  
Arthur J. Freeman ◽  
Gregory B. Olson

2011 ◽  
Vol 278 ◽  
pp. 192-197 ◽  
Author(s):  
Vsevolod I. Razumovskiy ◽  
A.Y. Lozovoi ◽  
Igor M. Razumovskii ◽  
Andrei V. Ruban

A new approach to the design of Ni-based polycrystalline superalloys is proposed. It is based on a concept that under given structural conditions, the performance of superalloys is determined by the strength of interatomic bonding both in the bulk and at grain boundaries of material. We characterize the former by the cohesive energy of the bulk alloy, whereas for the latter we employ the work of separation of a representative high angle grain boundary. On the basis of our first principle calculations we suggest Hf and Zr as “minor alloying additions” to Ni-based alloys. Re, on the other hand, appears to be of little importance in polycrystalline alloys.


1998 ◽  
Vol 548 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan

ABSTRACTIonic conductivities of solid CeO2:Y203 electrolytes were systematically investigated as a function of dopant concentration and sintering temperatures. The highest lattice conductivity occurred at 6–8% dopant concentration, and maximum grain boundary conductivity was observed at 10% dopant concentration. The sintering temperature was found to have a significant effect on the conductivities of the pellets. The samples sintered at lower temperatures (T≤140°C) showed higher grain boundary conductivity than those sintered at 150°C; this was found to be related to size-dependent-impurity segregation and precipitation at grain boundaries. The grain boundary conductivities as related to the microstructure are discussed by adopting different grain boundary models. Solute segregation and oxygen depletion at grain boundaries, which have been suggested to be responsible for the grain boundary resistivities in these samples, were examined by a microanalytical technique for small-grain-size samples.


1984 ◽  
Vol 144 (1) ◽  
pp. 182-195 ◽  
Author(s):  
M. Hashimoto ◽  
Y. Ishida ◽  
R. Yamamoto ◽  
M. Doyama ◽  
T. Fujiwara

Author(s):  
D.A. Smith ◽  
Z. Elgat ◽  
W. Krakow ◽  
A.A. Levi ◽  
C.B. Carter

There has been considerable progress made recently in understanding the atomic structure of grain boundaries in metals, semiconductors and ceramics. There is still, however, some dispute over whether a given grain boundary can exist with more than one non-symmetry-related structure. This has been shown experimentally to be the case in Ge for the first-order twin boundary lying parallel to the lateral {112} plane. In the present paper, it will be shown that a similar result holds for a more general grain boundary (actually Σ=137) lying close to the Σ=19 orientation; the Σ=19 boundary is formed by a rotation of 26.5° about a common <110> direction and lies along a common {31} plane. It is thus likely that a similar result will hold for other grain boundaries.Since it is essential to know that the different structures are not due to impurity segregation effects, bicrystals were grown from the melt with pre-oriented seeds using the Czochralski method following the approach of Bacmann as modified at Cornell by Skrotzki et al.


2022 ◽  
pp. 163732
Author(s):  
Song Tang ◽  
Tongzheng Xin ◽  
Ting Luo ◽  
Fan Ji ◽  
Chuanqiang Li ◽  
...  

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