A Model for Grain Junction in Polycrystalline Material and Effect of Temperature Changes on Related Phenomena

Abstract

Experimental evidences show that the material properties in an immediate vicinity of a Grain Junction (GJ) significantly differ from those in the bulk material. It is assumed that the material near the GJs is in some sort of a specific phase, and there is an interface between the GJ and the bulk material. Hsieh and Balluffi’s (1989) experimental data allows us to calculate the Laplace pressure at the interface. We consider the stress field induced by the Laplace pressure at the interface between the GJ and the bulk domain. The stresses extend the GJ domain and compress the material of adjacent grains. In the case of equilibrium they decrease as r⁻² for r→∞ where r is the distance from the geometrical center of the GJ to the point under consideration, and as r⁻¹ in the nonequilibrated case. We discuss the effect of grain anisotropy on the generation of shear stresses at grain boundaries.

The proposed model allows us to explain some phenomena specific to GJs. In particular, an elevation of the temperature causes an additional extension of the GJ domain, and compression of the adjacent grains. The model should be helpful for computations