High temperature low cycle fatigue characterization of equiaxed MAR-M-247

Abstract

Low cycle fatigue tests have been performed at 1038 • C on equiaxed MAR-M-247 under a mean compressive strain. Strain ranges assessed were 0.4, 0.6 and 0.8%, with this test program reflecting industrial gas turbine duty cycles. Fractographic analysis demonstrated transgranular crack propagation with intergranular fast fracture. Heavily oxidized secondary cracks were observed throughout. The details of a Lemaitre-Chaboche constitutive model that has been applied to the experimental stress-strain response are described. It was found that this model was capable of capturing both plastic shakedown and kinematic hardening effects with a high degree of accuracy (R 2 up to 0.997 and SSE up to 6E+4). The suitability of extending this model to address different strain histories are detailed.

Effect of Cooling Rate on the Microstructure and Mechanical Property of Nickel-Based Superalloy MAR-M247

“…MAR-M247 is a polycrystalline nickel-based superalloy and is widely employed in the aerospace industry in the production of advanced turbine blades and rotating parts due to its excellent casting properties and mechanical strength [ 1 , 2 , 3 , 4 ]. In order to improve its mechanical properties, many elements have been added to MAR-M247.…”

Nondestructive Methodology for Identification of Local Discontinuities in Aluminide Layer-Coated MAR 247 during Its Fatigue Performance

“…Since a high temperature significantly reduces the fatigue life of nickel superalloys [ 16 ], the application of thermal barrier coatings could further extend their fatigue life. The high-temperature fatigue response of the coated MAR 247 nickel superalloy has been widely studied in the literature [ 17 , 18 , 19 , 20 ]. It should be mentioned, however, that before the engine attains the high working temperature, the turbine blades are subjected to loading at ambient temperature.…”