Assessment of Infrared Thermography for Cyclic High-Temperature Measurement and Control

Infrared thermography (IRT), a non-invasive temperature measurement technique has been investigated and developed for use with cyclic hightemperature loading. The technique utilizes an infrared thermography camera (IRTC) and Rolls-Royce HE23 black thermal paint (TP). The TP is applied to a test-piece surface to provide a stable emissivity value and accurate temperature measurement for the duration of thermal cycling. Spot-welded type N thermocouples (NTCs) are utilized for accuracy validation of the IRTC … Continue reading Assessment of Infrared Thermography for Cyclic High-Temperature Measurement and Control

Non-invasive temperature measurement and control techniques under thermomechanical fatigue loading

A non-invasive temperature measurement, control and profiling technique has been investigated for use with thermomechanical fatigue loading. The technique utilises an infrared thermography camera and Rolls–Royce developed thermal paint to control andmonitor cyclic temperature. Thermal paint is used to maintain a stable surface emissivity upon the test piece. The accuracy of the technique is compared against type N thermocouples and a pyrometer for both temperature control and monitoring purposes. Diverse … Continue reading Non-invasive temperature measurement and control techniques under thermomechanical fatigue loading

Crack Growth of a Polycrystalline Nickel Alloy under TMF Loading

Thermo-mechanical fatigue (TMF) is an important factor for consideration when designing aero engine components due to recent gas turbine development, thus understanding failure mechanisms through crack growth testing is imperative. In the current work, a TMF crack growth testing method has been developed utilising induction heating and direct current potential drop techniques for polycrystalline nickel-based superalloys, such as RR1000. Results have shown that in-phase (IP) testing produces accelerated crack growth … Continue reading Crack Growth of a Polycrystalline Nickel Alloy under TMF Loading

An Empirical Approach to Correlating Thermo-mechanical Fatigue behaviour of a Polycrystalline Ni-base Superalloy

Assessment of thermo-mechanical fatigue behaviour of the polycrystalline nickel alloy RR1000 reveals a significant effect of phase angle on fatigue life. The current paper explores two scenarios: the first where the mechanical strain range is held constant and comparisons of the fatigue life are made for different phase angle tests; and secondly, the difference between the behaviour of In-phase (IP) and −180° Out-Of-Phase (OOP) tests … Continue reading An Empirical Approach to Correlating Thermo-mechanical Fatigue behaviour of a Polycrystalline Ni-base Superalloy

A Review of Thermo-Mechanical Fatigue behaviour in Polycrystalline Nickel Superalloys

Within the gas turbine engine, the high transient thermal stresses resulting from throttle movement from idle to high settings give rise to the phenomenon of thermo-mechanical fatigue (TMF). These effects have been widely explored for turbine blade materials, typically single crystal nickel alloys. More recently however, a combination of thinner disc rims and further increases in turbine entry temperature has led to a situation where TMF in disc materials … Continue reading A Review of Thermo-Mechanical Fatigue behaviour in Polycrystalline Nickel Superalloys