Isothermal and thermo-mechanical fatigue behavior of the nickel base superalloy Waspaloy™ under uniaxial and biaxial-planar loading

Fatigue behaviour of 16Mo3 steel at elevated temperatures under uniaxial as well as biaxial‐planar loading

“…Strain and temperature were measured on the opposite surfaces by attachment of a biaxial orthogonal extensometer and a thermocouple type K. The wires of thermocouple type K were separately welded with a distance of 1 mm to each other onto the surface in the centre of the cruciform specimens. The suitability of the biaxial‐planar test rig for isothermal and thermo‐mechanical fatigue experiments was proven in previous works of the authors' group …”

“…The stress within the cruciform specimens was calculated by using the partial unloading method which was already reported in several studies by the authors' group . With this method, the planar stress state can be calculated directly by means of the recorded strain and force data without any simulation.…”

Application of a Modified Stress−Strain Approach for the Fatigue‐Life Prediction of a Ferritic, an Austenitic and a Ferritic–Austenitic Duplex Steel under Isothermal and Thermo‐Mechanical Fatigue

“…This approach is based on the parameters of Zamrik and Renauld, and is extended by the plastic energy density as well as by an Arrhenius function (see Equation ). A more detailed description was given in previous work of the authors' group . The life‐prediction model of Zamrik and Renauld was applied for thermo‐mechanical fatigue lives with and without dwell times of the nickel‐base superalloy IN738LC, and improved the lifetime prediction significantly…”

“…Therefore, this damage parameter was not suitable for predicting the lifetimes. Thus, further fatigue life‐reducing effects were considered by a recently developed stress−strain approach . An improvement of the lifetime prediction was achieved by a modification of this parameter, which was able to predict the fatigue lives for the duplex, ferritic and austenitic stainless steels within the scatter band of a factor of two.…”

“…In order to ensure a constant cooling rate down to temperatures of 100 °C during thermo‐mechanical loading, three in‐line air nozzles were placed at an angle of 120° around the specimens. A more detailed description of both servo‐hydraulic systems is given in previous works of the authors' group …”