SEDL / STP / STP942-EB / STP24499S

Elevated Temperature Fatigue-Creep Behavior of Nickel-Base Superalloy IN 625

Bui-Quoc, T
Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec,

Gomuc, R
Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec,

Biron, A
Department of Mechanical Engineering, Ecole Polytechnique, Montreal, Quebec,

Nguyen, HL
Industrial Materials Research Institute, National Research Council Canada, Boucherville, Quebec

Masounave, J
Industrial Materials Research Institute, National Research Council Canada, Boucherville, Quebec

Pages: 15    Published: Jan 1988

Download this paper for $25 PDF (264K)          View License Agreement
Abstract

A research program has been carried out to establish the low-cycle fatigue and creep-fatigue behaviors of Inconel 625 at elevated temperatures (650 and 815°C). The main observations were related to the effect of temperature and of hold times. Under continuous cycling, a temperature increase from 650 to 815°C caused a reduction in the fatigue life by a factor of 2 at a high strain and by a factor of 3 at a low strain.

Tension hold times had little detrimental effect on cyclic life at 650°C concerning the life reduction with respect to continuous cycling; at 815°C, on the other hand, this became more significant. Compressive hold times also had a damaging effect on fatigue life, and this was larger than that associated with tensile hold times; in particular, it was very pronounced for low strain levels at 815°C.

An analysis of data using a life prediction method previously suggested for creep-fatigue combination loadings has also been carried out. The method takes into account the damaging effect due to a compression hold time separately from that due to a tensile hold time in interspersed creep-fatigue loadings. The overall correlation between theoretical calculations and experimental results is reasonably good, for strain levels ranging from 1.2 to 0.4%.