Most of the existent models on abnormal grain growth assume that a large preexistent grain is already present. However, abnormal grain growth is often found to develop from uniform grain size distributions. In this paper some possible causes for an abnormal grain to develop from uniform grain size distributiosn are examiend. First, a local fluctuation in the pinning frce is shown to be able to cause abnormal grain growth both in the presence of stable and unstable particels. Second, it is shown that a higher grain boundary mobility could also cause abnormal grain growth to develop from uniform grain boundary distributions. The circumstances in which it is not necessary for a high mobility to the maintained for abnormal grain growth to continue are also discussed. Based on the theoretical analysis it is concluded that the local environemtn, such as a locally lower pinning force or a higher mobility due to favorable orientation, can be a key factor in the development of abnormal grain growth from uniform grain boundary distributions.
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