Microstructural defects

If pH is unusually low within the tubercle, the floor may be heavily striated. Small, shallow parallel grooves will appear in the depressions beneath each tubercle (Fig. 3.24). The striations are caused by preferential corrosion along microstructural defects such as deformed metal. 

Most defects can be detected using one or more appropriate nondestructive testing techniques. However, in the absence of routine nondestructive testing inspections, identification of defects in installed equipment is generally limited to those that can be observed visually. Defects such as high residual stresses, microstructural defects such as sensitized welds in stainless steel, and laminations will normally remain undetected. Defects that can be detected visually have the following features ... 

Tritium and its decay product, helium, change the structural properties of stainless steels and make them more susceptible to cracking. Tritium embrittlement is an enhanced form of hydrogen embrittlement because of the presence of He from tritium decay which nucleates as nanometer-sized bubbles on dislocations, grain boundaries, and other microstructural defects. Steels with decay helium bubble microstructures are hardened and less able to deform plastically and become more susceptible to embrittlement by hydrogen and its isotopes (1-7). 

H. Leroux, J.C. Doukhan, and F. Langenhorst, Microstructural defects in experimentally shocked diopside A TEM characterization. Phys. Chem. Minerals 20, pp. 521-530(1994). 

Fig. 6a shows an example of a nanoscale breakdown driven thermochemical reaction induced microstructural defect in a poly-Si/Hft)2/SiOx gate stack... 

Insertion of propene into alkylzirconium model compounds derived from isospecific bis-indenyl catalysts may lead to low enantiospecificity [65]. Thus, site control alone does not lead to high stereoregularities. Molecular mechanics calculations [66] and a thorough analysis of the substituent effect on the statistical distribution of microstructure defects indicate that, firstly, the polymer chain assumes the energetically most favourable position with respect to the (asymmetric) site. According to Corradini, the indenyl ligand or the chlorine atoms of the lattice will direct the pol)rmer chain. The polymer chain occupies the "free space" near the site. In Fig. 6.21 we have schematically drawn this for the TiCls... 

S. J. Rosner, E. C. Carr, M. J. Ludowise, G. Girolami, and H. I. Erikson, Correlation of cathodoluminescence inhomogeneity with microstructural defects in epitaxial GaN... 

Chart 20. Chain Microstructure Defects Generated by Isolated Secondary (2,1) Insertion erythro (meso), threo (racemic) Secondary Units and 3,1 Unit ... 

The feasibility of the powder technology approach for obtaining layered cylindrical compacts from industrial silicate wastes, e. g. cullet glass and vitrified incinerator filter ash, was demonstrated [60], as shown in Figure 9. The materials underwent pressureless sintering after being compacted uniaxially in a die. They did not exhibit processing microcracks or other microstructural defects at the core/outer layer interfaces. 

Silicon carbide Fibres Mechanical properties Microstructure Defects... 

Corrosion Morphologies—Phase/Phase Morphologies and Microstructural Defects... 

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