Grain Boundary Atomic Structure and Microstructure of Bi-Sr-Ca-Cu-O, (Ti,Pb)-Sr-Ca-Cu-O and Pb-Sr-R (Rare Earth)-Ca-Cu-O Bulk Oxide Superconductors

1988 ◽  
Vol 138 ◽  
Author(s):  
P. L. Gai ◽  
M. A. Subramanian ◽  
J. Gopalakrishnan ◽  
E. D. Boyes
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Atomic Structure ◽  
Oxide Superconductors ◽  
Structure And Microstructure

Morphology and atomic structure of segregated grain boundaries in Cu-Sb

1992 ◽  
Vol 50 (1) ◽  
pp. 254-255
Author(s):  
R. W. Fonda ◽  
D. E. Luzzi
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Atomic Structure ◽  
Copper Alloys ◽  
Polycrystalline Materials ◽  
Grain Boundary Embrittlement ◽  
Boundary Embrittlement

The properties of polycrystalline materials are strongly dependant upon the strength of internal boundaries. Segregation of solute to the grain boundaries can adversely affect this strength. In copper alloys, segregation of either bismuth or antimony to the grain boundary will embrittle the alloy by facilitating intergranular fracture. Very small quantities of bismuth in copper have long been known to cause severe grain boundary embrittlement of the alloy. The effect of antimony is much less pronounced and is observed primarily at lower temperatures. Even though moderate amounts of antimony are fully soluble in copper, concentrations down to 0.14% can cause grain boundary embrittlement.

scholarly journals Electronic and Atomic Structure Studies of Rare Earth Metalloporphyrins by XAFS

2015 ◽  
Vol 71 ◽  
pp. 318-322 ◽  
Author(s):  
R.N. Mozhchil ◽  
A.P. Menushenkov ◽  
A.M. Ionov ◽  
S.I. Bozhko ◽  
V.D. Rumyantseva ◽  
...  
Keyword(s):  
Rare Earth ◽  
Atomic Structure

Atomic structure and defect energetics of LiCoO2 grain boundary

2016 ◽  
Vol 82 ◽  
pp. 81-86 ◽  
Author(s):  
Hak-Sung Lee ◽  
Chanbum Park ◽  
Chang-Seok Oh ◽  
Hun-Seok Lee ◽  
HyangIm Seo ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Atomic Structure

Improvement of Superplasticity in Fine-Grained Oxide Ceramics Based on the Concept of Grain Boundary Plasticity

2016 ◽  
Vol 838-839 ◽  
pp. 34-40
Author(s):  
Hidehiro Yoshida ◽  
Koji Morita ◽  
Byung Nam Kim ◽  
Koji Matsui ◽  
Yuichi Ikuhara ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Atomic Structure ◽  
Nucleation And Growth ◽  
Phenomenological Analysis ◽  
Research Field ◽  
Oxide Ceramics ◽  
Cavity Nucleation ◽  
Fine Grained ◽  
Experimental Strain ◽  
New Research

Superplasticity in fine-grained oxide ceramics has been generally elucidated on the basis of their experimental strain rate-flow stress relationship and phenomenological analysis of cavity nucleation and growth. It has been widely accepted that the high temperature superplastic flow and failure in ceramics is significantly influenced by the atomic structure and chemistry of grain boundaries. Such phenomenon cannot be explained based on the classical phenomenological analysis. Our research group has therefore proposed to establish a new research field, grain boundary plasticity, to describe the superplastic deformation related to the grain boundary atomic structure. This paper aims to point out the importance of the atomistic analysis of grain boundary to develop new superplastic ceramics.

Effect of rare-earth species on the wear properties of α sialon and β silicon nitride ceramics under tribochemical type conditions

2004 ◽  
Vol 19 (9) ◽  
pp. 2750-2758 ◽  
Author(s):  
Mark I. Jones ◽  
Kiyoshi Hirao ◽  
Hideki Hyuga ◽  
Yukihiko Yamauchi
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Wear Behavior ◽  
Rare Earth Oxide ◽  
Lower Amount ◽  
Boundary Phase ◽  
Wear Properties ◽  
Sintering Additives ◽  
Nitride Ceramics ◽  
Worn Surfaces

The wear properties under low loads of β Si3N4 and α sialon materials sintered with different rare-earth oxide sintering additives have been studied under dry sliding conditions using block-on-ring wear tests. All the worn surfaces showed an absence of fracture and smooth surfaces with the presence of an oxygen-rich filmlike debris indicating tribochemically induced oxidation of the surfaces. Extensive grain boundary removal was observed on the worn surfaces thought to be due to adhesion between this silicate phase and the tribochemically oxidized surfaces. The resistance to such oxidation and the properties of the residual grain boundary phase are thought to be important parameters affecting the wear behavior under the present testing conditions. For both the β Si3N4 and α sialon materials, there was an increase in wear resistance with decreasing cationic radius of the rare earth, thought to be due to improved oxidation resistance, and this was more remarkable in the case of the sialon materials where the incorporation of the sintering additives into the Si3N4 structure results in a lower amount of residual boundary phase.

Coercivity Enhancement of Nd-Fe-B HDDR Powder by Grain Boundary Diffusion Process with Rare-Earth Hydride

JOM ◽  
2018 ◽  
Vol 70 (5) ◽  
pp. 661-665 ◽  
Author(s):  
Hee-Ryoung Cha ◽  
Jae-Gyeong Yoo ◽  
Youn-Kyoung Baek ◽  
Dong-Hwan Kim ◽  
Hae-Woong Kwon ◽  
...  
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Diffusion Process ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion

Improvement of hot ductility of C-Mn Steel containing arsenic by rare earth Ce

2018 ◽  
Vol 115 (4) ◽  
pp. 419 ◽  
Author(s):  
Wenbin Xin ◽  
Jing Zhang ◽  
Guoping Luo ◽  
Ruifen Wang ◽  
Qingyong Meng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Grain Boundary ◽  
Boundary Segregation ◽  
Fracture Morphology ◽  
Grain Boundary Segregation ◽  
Hot Ductility ◽  
Ductility Trough ◽  
Reduction Of Area ◽  
Mn Steel ◽  
Ce Content

The effect of different Ce content on the hot ductility of C-Mn steel containing arsenic was investigated at the temperature ranging from 700 to 1100 °C conducting Gleebel-1500 thermal-mechanical simulator. The reduction of area (RA%) was used to evaluate the hot ductility. The 0.16 mass% As widened the ductility trough range and especially, decreased the RA value at 850–950 °C. Conversely, adding Ce in the steel could remedy the arsenic-induced hot ductility deterioration. Moreover, with the increase of Ce content from 0 to 0.035 mass%, the RA value at 800–950 °C significantly increased, compared to that of the arsenic steel. When the content of Ce reached 0.027–0.035 mass%, the RA value at 800–850 °C was even higher than that of steel without As. Besides, the corresponding fracture morphology was changed from intergranular feature to ductile and/or interdendritic feature. Grain refinement by Ce addition, the formation of arsenious rare earth inclusions and grain boundary segregation of Ce were considered to improve the hot ductility of the steel containing As.

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