The cyclic creep is dependent on the stress condition and temperature.
The stress conditions were amplitude, period and due time ratio. In order to know the stress period effect on the cyclic creep state, only the stress period was varied when other conditions were kept constant.
Test conditions in which the cyclic creep rate was lower than the static creep rate was used.
At the 0.50 Tm, the cyclic creep rate and strain differences due to the stress period alteration were small.
But at the 0.42 Tm, the cyclic creep rate and strain differences due to the stress period alteration were large.
The activation energy was measured from the typical Arrhenius plot near the 0.46 Tm.
The measured activation energy was 380 KJ/mole.
This showed the interaction between solute and dislocation.
The cyclic to static transient behaviours were observed at the 0.46 Tm and 0.42 Tm.
At the 0.46 Tm, the primary stage of the transient behaviour was more dominent at the shorter stress period.
At the 0.42 Tm, sigmoidal transient behaviour were observed at the stress period of 16 sec and 34 sec.
When this phenomenon occured, the cyclic creep rate was very reduced.
In the cyclic creep behaviour of Cu-Ni solid solution, the interaction force between solute and dislocation was dependent on the stress period.
This interaction force was larger at the short stress period and smaller at the long stress period.
The interaction force between dislocation and dislocation depended on the stress period, too.
This interaction force was large at the long stress period and small at the short stress period.
But the interaction of solute and dislocation was dominent. So, the creep rate and strain were reduced as the stress period became shorter.
