Yj. Baik et al., THE EFFECT OF ELASTIC-ANISOTROPY ON THE MIGRATION OF INTERGRANULAR LIQUID-FILMS AND THE PRECIPITATION OF A LIQUID-PHASE IN A CO-CU ALLOY, Acta metallurgica et materialia, 41(8), 1993, pp. 2385-2393
When a Co-20Cu (wt%) alloy prepared by liquid phase sintering at 1300-
degrees-C is heat-treated at 1150-degrees-C, the intergranular liquid
films and grain boundaries migrate, leaving behind a new solid solutio
n with reduced Cu content. The phenomenon is identical to that observe
d previously in Mo-Ni. The calculated driving force for the migration
is almost equal to the coherency strain energy in the solute diffusion
zone ahead of the migrating boundaries. The migrating liquid films sh
ow faceting with curved planes and edges. Their shape closely resemble
s the growth shapes predicted on the basis of the coherency strain ene
rgy with anisotropic elastic constants. During the heat-treatment, liq
uid precipitates form within grains and at grain boundaries, and they
also show faceting, which is consistent with orientation dependent coh
erency strain energy in the diffusion zone around the precipitates.