Constitutive modelling of an additively manufactured alloy for fatigue lifing in high temperature applications

Sammanfattning: The main objective of the work presented in this Licentiate thesis is to investigate and model the cyclic behaviour of an additively manufactured ductile nickel-based superalloy, with special emphasis on modelling the stabilised material behaviour, which is of interest for fatigue life predictions. Cyclic fatigue tests at different temperatures have been performed to investigate the cyclic mechanical behaviour of the material, where specimens built in different orientations have been used to also study the anisotropic behaviour of the material. Based on the tests, a constitutive description has progressively been developed and implemented in a finite element context that incorporates the anisotropic behaviour under both elastic and inelastic deformations. In addition, the room temperature crack initiation behaviour has been studied and modelled. This thesis is divided into two parts. The first part gives an introduction and background to the research, while the second part consists of three included papers.