[SY-I2] Symposium I-2

[SY-I2] Grain growth in ultrafine-grained thin films: A 3D problem

^○Ahu Oencue¹, Thorsten Halle², Dana Zoellner³ (1.Institute of Experimental Physics, Otto-von-Guericke University, Magdeburg, Germany, 2.Institute of Materials and Joining Technology, Otto-von-Guericke University, Magdeburg, Germany, 3.B CUBE Center for Molecular Bioengineering, TU Dresden, Dresden, Germany)

Grain microstructures of polycrystalline solids have an massive impact on materials properties. For investigations of bulk materials it is generally assumed that surfaces effects are insignificant. In contrast, in thin films surface effects become non-negligible. If during grain growth in such films the average grain size reaches the order of the layer thickness, grain growth slows down or even comes to a halt.

While analytic theories of nano- and microcrystalline grain growth are often in good agreement with numerical results using computer simulations with respect to, e.g., average growth kinetics, particularly analytic grain size distributions or topological correlations between grains rarely capture the experimental features. One reason of this disagreement can be found in the simple fact that the experimental samples are of 3D nature, but are commonly measured in 2D and compared with 2D simulations and analytic theories.

In the present work, we model grain growth in ultra-fine grained thin films using a three-dimensional Monte Carlo Potts model. In particular, we take into account that a reduction in grain size from micrometer to nanometer increases the importance of higher order grain boundary junctions, namely triple lines. The results are compared to experimental measurements of ultrafine-grained thin metallic films in three dimensions undergoing grain growth.