Effects of grain-boundary on elastic modulus of nanocrystalline materials

Reducing the grain size into nanometer scale for the polycrystalline, the mechanical properties associated with the grain size will, in general, represent size effects remarkably. With the decrement of grain size, the interface energy stemmed from the grain surface increase, and the gain-boundary influence on the mechanical properties of the materials also can be reinforced. In this paper, a framework is developed wit h considering the interface energy effects and grain-boundary effects with the aid of the continuum theory of mechanics to describe the grain-size effects on the elastic modulus of the nanocrystalline materials. Base on the numerical results, it is illustrated that the elastic modulus of nanocrystalline materials decreases with the reduction of the grain size in the scale of nanometer. In addition, compared with the present measurement, the proposed theoretical results can be agreeable well with the experimental results.