Molecular dynamics studies on the grain growth of nanocrystalline Ni and Ni3Al

摘要

With molecular dynamics simulations, the growth of face-centered-cubic nanocrystalline materials Ni and Ni3Al has been studied. It is found that grain-rotation induced grain coalescence and curvature-driven grain-boundary migration are dominant mechanisms in the nanograin growth. A detailed comparison of the nanograin growth between the two systems is discussed in terms of grain rotation and grain sliding. We also study the temperature effect and the size effect in the nanograin growth. The tendency of twinning in the nanograin growth is discussed. It is found that in Ni3Al, it seems more possible for nanograins to grow into twin-like structures than single crystal unless at very high temperatures.