Abstract: On the basis of the grain boundary equation by Hellman and corresponding analysis of Worner, this paper deals with the interaction range between the second-phase particle (SPP) and grain boundary (GB) as viewed from the applicability of grain boundary equation. Also, a new expression describing the interaction range has been derived, which solves the problem in theory that the interaction range between SPP and GB can only be qualitatively analyzed previously. It is shown that given the interaction position between SPP and GB the interaction range can be quantitatively determined by use of this expression.

Key words: second-phase particle, grain boundary, pinning force, surface free energy