The Non-Proportional Behaviour of a Nickel-Based Superalloy at Room Temperature, and Characterisation of the Additional Hardening Response by a Modified Cyclic Hardening Curve

A study was carried out where tension-torsion deformation strain-controlled tests were completed at Swansea University, to characterise the non-proportional hardening response of a nickel-based superalloy across a range of strain ranges. The data generated was used to assess the validity of a non-proportional cyclic hardening curve correction proposed by Socie and Marquis to represent the material’s hardening response. This modification involves the linear translation of … Continue reading The Non-Proportional Behaviour of a Nickel-Based Superalloy at Room Temperature, and Characterisation of the Additional Hardening Response by a Modified Cyclic Hardening Curve

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

Creep behaviour of Waspaloy under non-constant stress and temperature

Current creep models are derived using data from constant stress (or load) creep tests and are capable of accurately predicting creep behaviour when applied conditions are constant or near constant. However, analyses of creep curve shapes for the nickel based superalloy Waspaloy, when applied stress and/or temperature vary greatly during testing, have shown that predictive methods based purely on strain, time or life fraction are insufficient and cannot predict … Continue reading Creep behaviour of Waspaloy under non-constant stress and temperature

Recent Advances in Creep Modelling of the Nickel Base Superalloy, Alloy 720Li

Recent work in the creep field has indicated that the traditional methodologies involving power law equations are not sufficient to describe wide ranging creep behaviour. More recent approaches such as the Wilshire equations however, have shown promise in a wide range of materials, particularly in extrapolation of short term results to long term predictions. In the aerospace industry however, long term creep behaviour is not … Continue reading Recent Advances in Creep Modelling of the Nickel Base Superalloy, Alloy 720Li

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

Microstructural Characterization Of A Polycrystalline Nickel-Based Superalloy Processed Via Tungsten-Inert-Gas-Shaped Metal Deposition

Recent trials have produced tungsten-inert-gas (TIG)-welded structures of a suitable scale to allow an evaluation of the technique as an economic and commercial process for the manufacture of complex aeroengine components. The employment of TIG welding is shown to have specific advantages over alternative techniques based on metal inert gas (MIG) systems. Investigations using the nickel-based superalloy 718 have shown that TIG induces a smaller weld pool with less compositional … Continue reading Microstructural Characterization Of A Polycrystalline Nickel-Based Superalloy Processed Via Tungsten-Inert-Gas-Shaped Metal Deposition