Constitutive model of an additively manufactured ductile nickel-based superalloy undergoing cyclic plasticity

• Published in: International journal of plasticity Vol. 132; p. 102752
• Main Authors: Lindström, Thomas, Ewest, Daniel, Simonsson, Kjell, Eriksson, Robert, Lundgren, Jan-Erik, Leidermark, Daniel
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.09.2020; Elsevier BV
• Subjects: Additive manufacturing; Anisotropic material; Computer simulation; Constitutive models; Cycle jumping methods; Cyclic loading; Elastic plastic material; Fatigue life; Fatigue tests; Finite elements; Hysteresis loops; Isotropy; Low cycle fatigue; Material properties; Mathematical models; Nickel; Nickel base alloys; Parameters; Plastic deformation; Room temperature; Superalloys; Tensors; Cyclic loading; Anisotropic material; Elastic plastic material; Finite elements
• ISSN: 0749-6419; 1879-2154; 1879-2154
• DOI: 10.1016/j.ijplas.2020.102752

In this paper, a transversely isotropic elasto-plastic model based on the multilinear Ohno-Wang model was developed to simulate the cyclic behaviour of an additively manufactured ductile nickel-based superalloy. The transverse isotropy was taken into account by the incorporation of a structural tensor in the modelling framework. To calibrate the model, a number of uniaxial isothermal low-cycle fatigue tests were carried out on smooth specimens manufactured in three different orientations with respect to the building platform. The test specimens were subjected to different strain ranges and load ratios, as well as four different temperatures, namely room temperature, 400 °C, 500 °C and 600 °C. By using a cycle jumping procedure, where the material properties are changed from virgin parameters to mid-life parameters, the mid-life behaviour, commonly used for fatigue life predictions, of the concerned material could be simulated with good agreements to the performed experiments. To validate the results, the maximum and minimum stress, as well as the plastic strain range and hysteresis area from the simulated mid-life hysteresis loops were compared to the values obtained from the experiments. •The cyclic LCF behaviour of an AM nickel-based superalloy was studied.•A transversely isotropic elasto-plastic constitutive model was developed.•Kinematic hardening was modelled using the first Ohno-Wang model.•Elastic and plastic anisotropy due to the AM process is accounted for in the model.•The model predicts the experimental mid-life behaviour with good agreement.