ISSN:
1662-9779
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Physik
Notizen:
Nanomaterials, due to their fine grain sizes, exhibit enhanced mechanical properties.However, their low stability at also relatively low temperatures might limit their future applications.In the present work, a statistical model has been proposed in order to study grain growth processesin nanomaterials. The Hillert’s approach has been extended by incorporating two mechanisms ofgrowth for an individual grain: grain boundary migration – GBM - (diffusion based - continuous)and grain-rotation coalescence – GRC - (discontinuous). The influence of the grain size distributionon the grain growth process has been studied.The results show that the inclusion of GRC mechanisms results in a departure from the paraboliclaw of grain growth. Such a deviation has also been observed experimentally, especially innanomaterials. The results reveal that grain growth rate increases with higher dispersion of the finegrains and the rotation mechanism can initiate growth even with low dispersion. This causes asteady increase in the coefficient of variation which, after some time interval, decays tohomogeneity. This paper also demonstrates that the average rotation mobility which is aconsequence of the varying misorientation angle contributes up to about 50% of the overall averageboundary mobility
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.129.157.pdf
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