The major part of all material and microstructural data used for the modelling of nickel superalloy forgings are obtained from uniaxial laboratory tests with limited plastic strain and very simple thermo-mechanical history. At the same time, new challenges in near-net shape industrial forging require a high level of reliability of modelling prediction of metal flow, for predicting the risk of defects and microstructural transformation. A few recently conducted benchmarking studies have shown that despite the availability of various material models (including microstructural ones) embedded in commercial FE software, in many cases, the level of prediction remains unsatisfactory. This is especially true for Fast Industrial Forging Processes (like screw press or hammer forgings). This paper suggests a methodology for processing the results from industrial forgings for obtaining robust data for calibration, validation and improvement of material and microstructural models. This also can provide additional information on the material science behind the microstructural phenomena, which are problematic to capture and study using simple uniaxial tests.
Nickel-based superalloys are widely used in the aerospace sector for their mechanical properties, which are directly related to the microstructural and physical properties of these materials. JMAK-type models have been applied to this class of superalloys for the prediction of microstructural evolution phenomena such as recrystallisation. However, these models often lack a clear range of applicability. The majority of the successful applications normally address rather idealised processes (relatively slow forging, simple geometry). However, the real-world production environment generally involves complex strain paths and thermal histories. Thus, there arises the question of whether the JMAK-type models can be applied to such cases. This paper’s research focus is to investigate the applicability of JMAK-type models for such processes. To do this, screw press forging of disks was used to validate the in-built JMAK-type model of Inconel 718® available in DEFORMTM. In particular, the applicability of the model was examined using a comparison between the results from simulation and from metallographic analysis. At first, the appropriateness of the JMAK outputs in describing the observed microstructures was investigated and then quantitative results were evaluated. The model’s outputs were found to be insufficient in describing the observed microstructural states and additional parameters were deemed necessary. The model’s predictions ranged from a broadly good match, for which the model could be calibrated with a proposed new methodology, to a qualitative mismatch that highlights the limits of the model’s applicability.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.