Interfaces and Properties of Advanced Materials

2006 ◽  
Vol 512 ◽  
pp. 5-12
Author(s):  
Václav Paidar
Keyword(s):  
Grain Boundary ◽  
Structural Properties ◽  
Material Properties ◽  
Advanced Materials ◽  
Complex Relationship ◽  
Grain Boundary Engineering ◽  
Properties Of Materials ◽  
Boundary Classification

Internal interfaces are decisive for many properties of materials. Both functional and structural properties of interfaces are briefly reviewed on selected examples. Approaches to the grain boundary classification are discussed in the context of the complex relationship between microstructure and material properties. Implications for grain boundary engineering are mentioned.

Anisotropic Behaviour of Grain Boundaries

2005 ◽  
Vol 482 ◽  
pp. 63-70 ◽  
Author(s):  
Václav Paidar ◽  
Pavel Lejček
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Polycrystalline Materials ◽  
Grain Boundary Engineering ◽  
Interfacial Dislocation ◽  
Special Character ◽  
Boundary Properties ◽  
Properties Of Materials ◽  
Boundary Classification ◽  
Boundary Chemistry

Grain boundaries are decisive for many properties of materials. Due to short-range stress field their influence is primarily based on their atomic structure. Special character of grain boundary properties related to their structure, follows from the nature of atomic arrangements in the boundary cores, from the interfacial dislocation content and from the boundary mobility. All those aspects of boundary behaviour are strongly influenced by the boundary chemistry including various segregation phenomena. Approaches to the boundary classification and the interpretation of recent experimental results are discussed in the context of the complex relationship between microstructure and material properties. Such findings are essential for Grain Boundary Engineering proposed to improve the performance of polycrystalline materials.

A new challenge: grain boundary engineering for advanced materials by magnetic field application

2006 ◽  
Vol 41 (23) ◽  
pp. 7747-7759 ◽  
Author(s):  
Tadao Watanabe ◽  
Sadahiro Tsurekawa ◽  
Xiang Zhao ◽  
Liang Zuo ◽  
Claude Esling
Keyword(s):  
Magnetic Field ◽  
Grain Boundary ◽  
Field Application ◽  
Advanced Materials ◽  
Grain Boundary Engineering ◽  
Magnetic Field Application

Electron Scattering with an Atomic Sized Probe

2000 ◽  
Vol 6 (S2) ◽  
pp. 102-103
Author(s):  
J. Silcox
Keyword(s):  
Grain Boundary ◽  
Electron Scattering ◽  
Material Properties ◽  
Boundary Energy ◽  
Hole Density ◽  
Grain Boundary Energy ◽  
Properties Of Materials ◽  
Gap States ◽  
Atomic And Electronic Structure

It is the presence of local variations in atomic and electronic structure that often gives rise to intriguing properties of materials. Control of material properties then rests on detection of the local variations in the materials, determination of the origin of those variations and then understanding how such variations can be controlled to achieve a desired functionality. Recent examples using STEM with an atomic sized probe (∼2.2 Å) include studies of the bonding at grain boundaries in nickel rich Ni3Al doped with boron. EELS measurements revealed changes in the d-hole density-of-states that were used to estimate changes in the electronic contribution to the grain boundary energy. These changes in grain boundary strength correlated with a change in fracture from an intra- to an inter-granular mode. In another example, the observation of metal induced gap states at Cu/MgO interfaces provided evidence that the dipole moment across that interface was relatively low.

Metallurgical Effects of Grain Boundary Ledges

1977 ◽  
Vol 35 ◽  
pp. 126-129
Author(s):  
L.E. Murr
Keyword(s):  
Grain Boundary ◽  
Quantitative Data ◽  
Mechanical Treatment ◽  
Unit Length ◽  
Physical And Mechanical Properties ◽  
Direct Observations ◽  
Transmission Electron ◽  
Properties Of Materials ◽  
Thermo Mechanical Treatment ◽  
Ledge Density

Ledges in grain boundaries can be identified by their characteristic contrast features (straight, black-white lines) distinct from those of lattice dislocations, for example1,2 [see Fig. 1(a) and (b)]. Simple contrast rules as pointed out by Murr and Venkatesh2, can be established so that ledges may be recognized with come confidence, and the number of ledges per unit length of grain boundary (referred to as the ledge density, m) measured by direct observations in the transmission electron microscope. Such measurements can then give rise to quantitative data which can be used to provide evidence for the influence of ledges on the physical and mechanical properties of materials.It has been shown that ledge density can be systematically altered in some metals by thermo-mechanical treatment3,4.

Grain boundary segregation in metals

1992 ◽  
Vol 50 (2) ◽  
pp. 1204-1205
Author(s):  
C.L. Briant
Keyword(s):  
Fracture Surface ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Material Properties ◽  
Electron Spectroscopy ◽  
High Vacuum ◽  
Boundary Segregation ◽  
Grain Boundary Segregation ◽  
Local Concentration ◽  
The One

Grain boundary segregation is the process by which solute elements in a material diffuse to the grain boundaries, become trapped there, and increase their local concentration at the boundary over that in the bulk. As a result of this process this local concentration of the segregant at the grain boundary can be many orders of magnitude greater than the bulk concentration of the segregant. The importance of this problem lies in the fact that grain boundary segregation can affect many material properties such as fracture, corrosion, and grain growth.One of the best ways to study grain boundary segregation is with Auger electron spectroscopy. This spectroscopy is an extremely surface sensitive technique. When it is used to study grain boundary segregation the sample must first be fractured intergranularly in the high vacuum spectrometer. This fracture surface is then the one that is analyzed. The development of scanning Auger spectrometers have allowed researchers to first image the fracture surface that is created and then to perform analyses on individual grain boundaries.

Relationships Between Grain Boundary Structure and Material Properties

1980 ◽  
Vol 38 ◽  
pp. 366-369
Author(s):  
Brian Ralph ◽  
Barlow Claire ◽  
Nicola Ecob
Keyword(s):  
Grain Boundary ◽  
Material Properties ◽  
Main Property ◽  
Grain Structure ◽  
Boundary Structure ◽  
Grain Boundary Structure ◽  
Property Changes

This brief review seeks to summarize some of the main property changes which may be induced by altering the grain structure of materials. Where appropriate an interpretation is given of these changes in terms of current theories of grain boundary structure, and some examples from current studies are presented at the end of this paper.

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