The effect of Sn segregation at grain boundary on the steady-state creep of Cu-10 wt % Sn alloy

Abstract

The effect of Sn solutes segregating into grain boundaries on the steady-state creep characteristics was studied for wires of a Cu-10 wt % Sn alloy having various grain diameters,d. The creep tests were performed for samples in theα-phase in the temperature range: (0·5–0·58 T_m). The steady state creep rate,ε _s, was found to vary linearly withd. The variation in the stress sensitivity parameter,m, was found to be much less appreciable for large grains (>50μm). Activation energy calculation showed that two competitive mechanisms are operating for creep deformation, namely, dislocation climb and viscous motion of matrix dislocations due to dragging of Sn atmosphere. A value of 6·74 kJ/mol was obtained for the binding energy between a Sn atom and the dislocation, while the binding energy between a vacancy and the Sn atom was found to be 33·71 kJ/mol.