Creep and Structure Parameters Near the Transformation Temperature of Sn-1 wt% Pb Alloy

Sn-1 wt % Pb alloy is studied in tensile creep at different temperatures
between 323 and 383K and constant stresses varying between 14.1 and 16.0
MPa. Both the creep and the microstructure parameters show one
transformation temperature at 353K. The transient creep parameters β and n
are affected by both the applied stress and the working temperature and have
values ranging from 1.36x10-4 to 34x10-4 and from 0.878 to 0.975, respectively.
The activation energies of the transient creep around 353K are found to be
(50±4) and (86±7)kJ/ mol, which identify dislocation mechanisms. The
activation energy of the steady state creep has values of (79±5) and (106±9)
kJ/mol around the transformation temperature which characterizes Coble creep < br />and viscous grain boundary sliding mechanisms, respectively. The X-ray
diffraction analysis shows that both the ratio (c/a) and the integral intensity (I)
of the Sn-rich phase have minima at the transformation temperature.