Effect of hold times on the elevated temperature fatigue crack growth behavior of Inconel 718 alloy

The effect of tensile hold times on the fatigue crack growth rate of Inconel 718 was studied at 923 K. It was found that the superimposition of hold times (Th) can produce a drastic increase in the fatigue crack growth rate. Potential drop technique was used to analyse the crack propagation which takes place in certain conditions either during the cyclic part of the loading or during the dwell period. In this high strength and low ductility material an expression has been found for an upperbound of the crack growth rate. (author)