Grain-boundary chemistry

Relationship of Grain Boundary Chemistry and Fracture in an Aqueous Environment (AES)... 

POSTER TITLE Effect of Microstructure and Grain Boundary Chemistry on the Corrosion Performance of AA7050... 

The role of grain boundary chemistry on properties cannot be overemphasized. For many ceramics, the presence of small amounts of impurities... 

Good varistor behavior Control of grain boundary chemistry... 

Effect of microstructure and grain boundary chemistry on boundary mobitity... 

Sakuma T, Ikuhara Y, Takigawa Y, Thavomiti P (1997) Importance of grain boundary chemistry on the high-temperature plasdc flow in oxide ceramics. Mater Sci Eng A-Struct... 

Chiang, Y.-M. and Takaki, T., Grain-boundary chemistry of barium titanate and strontium titanate I. High-temperature equilibrium space charge, J. Am. Ceram. Soc., 73, 3278-85, 1990. 

Some surface analysis instruments are equipped with apparatus to fracture or cleave a material within the UHV chamber to expose a fresh surface for analysis. Metal samples are routinely fractured in UHV to expose grain boundaries. This permits XPS or AES detection of bulk impurities that have segregated to grain boundaries, for example. Grain boundary chemistry is of great interest to metallurgists for many reasons. As noted, even under UHV conditions, a limited time is available for contamination-free analysis of freshly exposed surfaces. 

Three techniques (FEGSTEM/EDX, Auger spectroscopy and APT) provide information on grain boundary chemistry. There are advantages and disadvantages of each as summarised in Table 9.3. Assumptions are involved in the interpretation of data from each of the techniques and there have been relatively few studies in which two or more of these techniques have been applied to the same material conditions. 

Similar final densities were achieved for all samples suggesting that method of sintering aid deposition does not affect denslfication for these HIP parameters. However, grain boundary chemistry may be different, Microstructure and grain boundary uniformity of these samples will be examined using STEM. 

The influence of grain boundary chemistry and structure of Alloy 600 (Mat.-No. 2.4816 here Ni-16Cr-9Fe-C-B) on the stress corrosion cracking behaviour in high purity deaerated water with 18 cm (< 5 pg/1 oxygen) at 347 C has been re-... 

The Influence of Grain Boundary Chemistry and Structure on the Intergranular Attack and Intergranular Stress Corrosion Cracking of Austenitic Alloys... 

We note that several of these topics are also discussed in Chapter 24 by Takasugi in this volume. These common items are used in that chapter to discuss grain-boundary chemistry and structure, whereas here they are used to discuss intergranular fracture. 

Grain boundary chemistry due to irradiation-induced chromium depletion and nickel enrichment and impurity (e.g., silicon, phosphorous) segregation, since these can affect the oxidation kinetics at the strained crack tip... 

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