Temperature
Cyclic softening was shown with temperature at 1.0% strain range for 91A and 91B of one step heat treatment in
Fig. 2. Cyclic softening behavior was a little different with temperature for 91A and 91B but increased greatly at
600°C irrespective of 91A and 91B. Comparing with cyclic softening at RT, cyclic softening increased a little at
300°C and 400°C but was almost the same at 500°C for 91A. Cyclic softening was almost same at 300°C and 400°C
and increased at 500°C for 91B one step heat treatment. Cyclic softening increased greatly to about 250 cycles and
increased gradually above this cycle. Cyclic softening trend with cycles was almost the same at all temperature for
91A and 91B.