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• Crack closure explains crack growth behaviour for CM 247 LC. • Crack closure explains crack growth under prolonged hold times. • Simulations can replicate plasticity-induced crack closure. • The proposed analytical model estimates crack opening levels. The crack growth behaviour of the alloy CM 247 LC is investigated for out-of-phase TMF and isothermal tests at the same temperature as the minimum temperature in the TMF tests. The results suggest that it is possible to characterise crack growth behaviour if experimental corrections for crack closure are accounted for. The replication of these experimental tests using a numerical FE-solver results in similar crack growth behaviour, suggesting that the main mechanism in place is plasticity-induced crack closure. A pragmatic analytical model to characterise crack closure including hold time effects is proposed. The comparison of the response from this model with the experimental and numerical results suggests that the proposed analytical model is capable to approximate crack closure effects for cases where substantial creep deformation is to be expected. [ABSTRACT FROM AUTHOR]

• IP TMF crack propagation tests at high temperature with extended hold times. • Crack closure evaluated experimentally and numerically. • Numerical simulations verified with experiments. • Crack closure can explain crack growth under test conditions. Crack closure effects are known to have a large impact on crack growth behaviour. In this work, tests were performed on Inconel 792 specimens under TMF loading conditions at 100–850 °C with extended hold times at tensile stress. The effective stress-intensity range was estimated experimentally using a compliance-based method leading to the conclusion that crack closure appears to have a primary impact on the crack growth behaviour for this material under the conditions studied. The crack closure behaviour for the tests was successfully modelled using numerical simulations, including creep. [ABSTRACT FROM AUTHOR]