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MM: Fachverband Metall- und Materialphysik

MM 32: Microstructure and Phase Transformations

MM 32.2: Vortrag

Mittwoch, 14. März 2018, 10:30–10:45, TC 010

Investigating the size advantage of potentially abnormal grains — •Dana Zöllner¹ and Paulo R. Rios² — ¹B CUBE Center for Molecular Bioengineering, TU Dresden, Arnoldstr. 18, 01307 Dresden, GERMANY — ²Escola de Engenharia Industrial Metalurgica, Universidade Federal Fluminense, Av. dos Trabalhadores, 420 Volta Redonda, RJ, 27255-125, BRASIL

The well-investigated process of curvature driven grain growth progresses by the motion of grain boundaries to the center of their curvature. In polycrystalline grain boundary networks this leads over time to a decrease in the total interfacial area and therewith also to a decreasing interfacial free energy. As a result, the grain microstructure evolves such that it has a unimodal size distribution. In contrast, abnormal grain growth proceeds in such a way that certain grains show an exaggerated growth, which leads to changes in the average growth law as well as to a bimodal size distribution. In the present work, Monte Carlo computer simulations of grain growth are employed to determine how grains showing a very large size advantage behave within a matrix of finer grains that can grow without restrictions. We demonstrate that true abnormal grain growth does not develop from those large grains. In fact, the large grains tend to decrease their size advantage over time and may eventually be *captured* by the grain size distribution of the matrix. However, another phenomenon may happen: the persistence of the size advantage of these grains may lead to pseudo-abnormal grain growth.