On the uniaxial mechanical behaviour of an advanced nickel base superalloyat high temperature

The uniaxial mechanical behaviour of an advanced nickel base superalloy has been studied under strain-con trolled cyclic loading at two elevated tempe ratures, 300 and 650 degreesC. High-temperature related features, such as a transition from initial cyclic hardening to softening and stress relaxatio n during load-holding periods, were observed. The material's low cycle fati gue life experienced heavy reduction with increase in temperature and strai n range. Using constitutive models for cyclic plasticity/viscoplasticity, a ttempts were made to simulate the stabilized cyclic loops for different str ain ranges at both temperatures. The model parameters were determined simul taneously. Comparison of the simulated and experimental results is made for the stabilized cyclic loops and the stress relaxation behaviour. (C) 2001 Elsevier Science Ltd. All rights reserved.