Creep by Grain-Boundary Mass Transport in Binary Copper Alloys

Abstract

Creep has been investigated in Cu–Ni and Cu–Sn alloys in the region where the process is controlled by grain-boundary mass transport. The addition of Ni to Cu causes a reduction in the rate of creep and this is interpreted in terms of the change of grain-boundary diffusivity on alloying. The addition of small amounts of Sn causes increases in creep rate corresponding to the expected increase in atomic mobility on adding a solute of lower melting point. Further additions, however, cause appreciable reductions in creep rate associated with the precipitation of € phase. In this material behaviour is interpreted in terms of the. balance between the requirements of diffusional accommodation at triple points and that at grain-boundary particles.