Thermo-Mechanical Fatigue of the Nickel Base Superalloy IN738LC for Gas Turbine Blades

Abstract

A more accurate life prediction for gas turbine blade takes into account the material behavior under the complex thermo-mechanical fatigue (TMF) cycles normally encountered in turbine operation. An experimental program has been carried out to address the thermo-mechanical fatigue life of the IN738LC nickel-base superalloy. High temperature out-of-phase and in-phase TMF experiments in strain control were performed on superalloy materials. Temperature interval of 450-850 was applied to thermo-mechanical fatigue tests. The stress-strain response and the life cycle of the material were measured during the test. The mechanisms of TMF damage is discussed based on the microstructural evolution during TMF. The plastic strain energy based life pediction models were applied to the stress-strain history effect on the thermo-mechanical fatigue lives.

Enhanced laser weldability of an aerospace superalloy by thermal treatment

“…On the other hand, transgranular mode of failure implies that grain boundaries are not significant in the failure process of IP-TMF of a polycrystalline material. While some authors have argued that in IP-TMF of a polycrystalline material is entirely transgranular or a combination with intergranular [10-13], some other authors have concluded that it is intergranular [14, 15]. Hence, the need in this work for a systematic approach to understanding the mode of failure during IP-TMF.…”

Design and characterization of a Raman-scattering-based sensor system for temporally resolved gas analysis and its application in a gas turbine power plant

“…Moreover, a temporal increase of flame temperature may lead to an increase of pollutant emission, e.g. of nitrogen oxide [8,9], and of course may cause damage to the mechanical parts of the turbine [10]. Therefore fast gas analysis is required to facilitate controlling the gas supply for a quick correction due to fluctuations of the gas composition.…”