The steady-state creep mechanism of a 70Cu-30Ni alloy was studied in the temperature range of 400-700 ℃ (0.44-0.64Tm) and in the constant stress range of 1.5-34.3Kg/㎟ (14.7-336.4Mpa). Using the results obtained from strain transient dip test, stress change creep test, TEM investigation and high temperature tensile test, corelation of those parameters-$σ^*$, $σ_i$, $σ_a$ dislocation structure and density were made and discussed for the interpretation of the creep behavior. Form the above experimental data, steady-state creep rate can be expressed by as follow:
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where $\acute{A}$ is the temperature and structure independent term whose value is $1.84×10^{-4}$, $n^*=2.6$ and $α_{0.05}$ is proof stress at engineering strain e=0.05. From the above equation, it is thought that the same value of $\frac{σ^*}{σ_{0.05}}$ at various temperatures means the same external effect on the steady-state creep rate. In conclusion, the creep deformation mechanism of the alloy is best explained by the non-conservative motion of jogged screw dislocation model, because of the facts that the stress exponent, n, is observed to be a function of applied stress and test temperature, that the apparent creep activation energy decreases as the applied stress increases and that the experimentally obtained activation length, $1^*$, has the order of $10^2 - 10^3$$\dot{A}$.
