Abstract
This paper studies the multiaxial creep-fatigue damage evaluation for SUS304 stainless steel at 973K. Strain controlled biaxial tension-compression low cycle fatigue and creep-fatigue tests were carried out using cruciform specimens under two strain waveforms at three principal strain ratios. The principal strain ratio is φ =εx/εy ; εx and εy are the principal strains in x and y directions, respectively. Low cycle fatigue and creep-fatigue lives decreased with increasing the principal strain ratio in Δεy constant tests. Cracks in creep-fatigue tests at larger principal strain ratio initiated earlier than those at lower principal strain ratio. Earlier and faster void growth was observed in creep-fatigue tests at larger principal strain ratio. An equation taking account of the contribution of x and y directional strains to void growth was proposed. Directional void growth and determination of two principal strain directions based on the void observations were discussed.
