Normal Vs Abnormal
In common with recovery and recrystallisation, growth phenomena can be separated into continuous and discontinuous mechanisms. In the former the microstructure evolves from state A to B (in this case the grains get larger) in a uniform manner. In the latter, the changes occur heterogeneously and specific transformed and untransformed regions may be identified. Discontinuous grain growth is characterised by a subset of grains growing at a high rate and at the expense of their neighbours and tends to result in a microstructure dominated by a few very large grains. In order for this to occur the subset of grains must possess some advantage over their competitors such as a high grain boundary energy, locally high grain boundary mobility, favourable texture or lower local second-phase particle density.
Read more about this topic: Grain Growth
Famous quotes containing the words normal and/or abnormal:
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—Lawrence Balter (20th century)
“In abnormal times like our own, when institutions are changing rapidly in several directions at once and the traditional framework of society has broken down, it becomes more and more difficult to measure any type of behavior against any other.”
—John Dos Passos (1896–1970)