Mechanism based flow stress model for alloy 625 and alloy 718

Research output: Contribution to journalArticle

Abstract

To predict the final geometry in thermo-mechanical processes, the use of modeling tools is of great importance. One important part of the modeling process is to describe the response correctly. A previously published mechanism-based flow stress model has been further developed and adapted for the nickel-based superalloys, alloy 625, and alloy 718. The updates include the implementation of a solid solution strengthening model and a model for high temperature plasticity. This type of material model is appropriate in simulations of manufacturing processes where the material undergoes large variations in strain rates and temperatures. The model also inherently captures stress relaxation. The flow stress model has been calibrated using compression strain rate data ranging from 0.01 to 1 s−1 with a temperature span from room temperature up to near the melting temperature. Deformation mechanism maps are also constructed which shows when the different mechanisms are dominating. After the model has been calibrated, it is validated using stress relaxation tests. From the parameter optimization, it is seen that many of the parameters are very similar for alloy 625 and alloy 718, although it is two different materials. The modeled and measured stress relaxation are in good agreement.

Details

Authors
  • Andreas Malmelöv
  • Martin Fisk
  • Andreas Lundbäck
  • Lars Erik Lindgren
Organisations
External organisations
  • Luleå University of Technology
  • Malmö University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Metallurgy and Metallic Materials

Keywords

  • Dislocation density, Flow stress model, Inconel, Material model, Stress relaxation
Original languageEnglish
Article number5620
Number of pages17
JournalMaterials
Volume13
Issue number24
Publication statusPublished - 2020
Publication categoryResearch
Peer-reviewedYes