Effects of surface and grain boundary on temperature-pressure nano-phase diagrams of nanostructured carbon

2022 ◽  
Vol 207 ◽  
pp. 114267
Author(s):  
Xue Yao ◽  
Guo-Jun Liu ◽  
Xing-You Lang ◽  
Hong-Dong Li ◽  
Yong-Fu Zhu ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Phase Diagrams ◽  
Nanostructured Carbon

Phase Relationship Studies of Silicon Nitride System—A Key to Materials Design

1992 ◽  
Vol 287 ◽  
Author(s):  
T.S. Yen ◽  
W.Y. Sun
Keyword(s):  
Elevated Temperature ◽  
Silicon Nitride ◽  
Grain Boundary ◽  
Phase Behavior ◽  
Phase Diagrams ◽  
Room Temperature ◽  
Phase Relationship ◽  
Materials Design ◽  
Basic Approach ◽  
System A

ABSTRACTAdditions and revisions to several of the most important phase diagrams and phase behavior diagrams in the silicon nitride field are reviewed in this work, with emphasis on the Y-Si-A1-O-N system. This information is further used to make observations on the promising silicon nitride systems containing either highly refractory grain boundary phases or compatible matrix phases of desirable properties. Examples are provided to illustrate the advantage of such a basic approach to materials design. Hardness, toughness, strength at room temperature and elevated temperature and even sinterability can all be improved by adopting such an approach.

Effects of Surface and Grain Boundary on Temperature-Pressure Nano-Phase Diagrams

2021 ◽  
Author(s):  
Xue Yao ◽  
Guo-Jun Liu ◽  
Xing-You Lang ◽  
YongFu Zhu ◽  
Qing Jiang
Keyword(s):  
Grain Boundary ◽  
Phase Diagrams

Field Emission from Carbon Systems

2000 ◽  
Vol 621 ◽  
Author(s):  
John Robertson
Keyword(s):  
Carbon Nanotubes ◽  
Grain Boundary ◽  
Field Emission ◽  
Electron Affinity ◽  
Field Enhancement ◽  
Diamond Like Carbon ◽  
Electron Field Emission ◽  
Nanostructured Carbon ◽  
Boundary States ◽  
Electron Field

ABSTRACTElectron field emission from diamond, diamond-like carbon, carbon nanotubes and nanostructured carbon is compared. It is found that in all practical cases that emission occurs from regions of positive electron affinity with a barrier of ∼5 eV and with considerable field enhancement. The field enhancement in nanotubes arises from their geometry. In diamond, the field enhancement occurs by depletion of grain boundary states. In diamond-like carbon we propose that it occurs by the presence of sp2-rich channels formed by the soft conditioning process.

Grain boundary phase transitions and phase diagrams

2001 ◽  
Vol 3 (8) ◽  
pp. 1113-1115 ◽  
Author(s):  
B.B Straumal ◽  
P Ziȩba ◽  
W Gust
Keyword(s):  
Phase Transitions ◽  
Grain Boundary ◽  
Phase Diagrams ◽  
Boundary Phase

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Two Investigations into Grain Boundary Structure

1977 ◽  
Vol 35 ◽  
pp. 688-691
Author(s):  
P. Humble
Keyword(s):  
Grain Boundary ◽  
Dark Field ◽  
Boundary Structure ◽  
Boundary Dislocation ◽  
Bright Field ◽  
Intrinsic Structure ◽  
Weak Beam ◽  
Grain Boundary Structure ◽  
Independent Information ◽  
Diffraction Patterns

There has been sustained interest over the last few years into both the intrinsic (primary and secondary) structure of grain boundaries and the extrinsic structure e.g. the interaction of matrix dislocations with the boundary. Most of the investigations carried out by electron microscopy have involved only the use of information contained in the transmitted image (bright field, dark field, weak beam etc.). Whilst these imaging modes are appropriate to the cases of relatively coarse intrinsic or extrinsic grain boundary dislocation structures, it is apparent that in principle (and indeed in practice, e.g. (1)-(3)) the diffraction patterns from the boundary can give extra independent information about the fine scale periodic intrinsic structure of the boundary.In this paper I shall describe one investigation into each type of structure using the appropriate method of obtaining the necessary information which has been carried out recently at Tribophysics.

Sign in / Sign up

Export Citation Format

Share Document