Wetting and structural transition induced by segregation at grain boundaries: a monte carlo study.

Wetting of the Sigma = 5 (310) <001> symmetrical tilt grain boundary (GB) close to the solubility limit in the Cu(Ag) solid solution has been observed by means of Monte Carlo simulations at T = 600 K. More precisely, a finite thickness film almost pure in Ag, separating the two initial Cu(Ag) grains, can be obtained from a critical intergranular germ induced by the strong segregation of Ag in the GB. As this film is actually a single crystal, this implies a complete rearrangement of the GB core structure. Thus the initial GB is replaced by two Cu(Ag)/Ag(Cu) interfaces. Evidence is presented for the increase of the film thickness when approaching the solubility limit, as expected in wetting phenomena.