DEPENDENCE OF CREEP CHARACTERISTICS ON TEMPERATURE AND APPLIED STRESS IN ZN-1.0 WT-PERCENT CU DURING TRANSFORMATION

The change in the transient and steady state creep deformation of zinc-1.0 wt.\% Cu alloy was studied under various constant stresses ranging from 45.80 MPa to 56.02 MPa in the temperature range from 473 K to 573 K. From the transient creep results, the peak values of transient creep parameters B and n found in this temperature zone can be ascribed to dissolution of epsilon-phase (Cu-rich phase). The transient creep parameter B is related to the steady state creep rate epsilon(st) through the exponent gamma. This exponent has been found to range from 0.8 to 0.3. At the dissolution temperature (513 K) of epsilon-phase, the steady state strain sensitivity parameter has been 0.30 +/- 0.01 at the steady state strain peaks which is characteristic of dislocation climb along epsilon-grain boundaries. The activation energies of the transient and steady state creep in the phase transformation region have been found to be 42 kJ/mole and 63 kJ/mole characterizing the cross slipping of dislocations and dislocation climb along grain boundaries, respectively.