History effects on the cyclic stress—strain response of a polycrystalline and single crystal nickel-base superalloy

Isothermal high strain tension—compression load cycling experiments were carried out on polycrystalline IN100 and single crystal SRR99 specimens, the latter with the stress axis in the [001] cystallographic direction. Testing was conducted at 50°C intervals in the range 650–1000°C at strain rates of 3 × 10−4 s−1 and lower. The isothermal data were used to deduce anisothermal hysteresis loops which are compared with (a) those obtained experimentally from true ‘thermo-mechanical’ (TMF) cyclic tests and (b) those calculated from the strain—temperature sequence measured in the constrained tip region of a thermally shocked linear wedge. The isothermal stress—strain data provided a very good prediction of the anisothermal behaviour.