EFFECT OF CYCLIC TEMPERATURES ON STRESSRUPTURE LIFE OF A Ni-BASE SUPERALLOY

The stress-rupture life of a Ni-base superalloy has been evaluated under the cyclic temperatures by using the sinusoidal or the specified program-controlled waveform. It was shown that its stress-rupture life is considerably reduced by the temperature cycle. The extent of reduction is depended on the amplitude of the cycle. The formulation of life prediction for specified program-controlled temperature cycle is proposed. The fracture surface of the superalloy has also been observed by SEM.