Effects of average grain size and misorientation angle on the deformation behaviour of nanocrystalline grain structures

This study reports an investigation using finite element analysis to study the behaviour of nanocrystalline grain structures during severe plastic deformation. The effects of average grain size and misorientation angle on the deformation are examined in order to evaluate how microstructural features might explain the observed increase in strength of nanocrsytalline metals. A polycrystal model is generated using a planar tessellation with randomly orientated grains with the numbers of grains being 15, 22 and 34. The simulated results show that the grain size and the grain misorientation angle have significant effects on the stress distribution and average stress within the polycrystalline area. This study thus successfully demonstrated a relatively efficient finite element technique which makes the stress field dependent on the grain size and the angle of misorientation between grains.