Skip to main content

Computer-Aided Design Of Revolutionary Superalloys

Periodic Reporting for period 1 - CADORS (Computer-Aided Design Of Revolutionary Superalloys)

Reporting period: 2015-09-01 to 2016-08-31

Metallic alloys are used in many industrial applications, needing the constant development of new materials with tailored properties. However, the relations between composition, processing and properties are so complex that alloy development cannot be made anymore by a traditional trial-and-error procedure, and there is a growing need for models able to predict the behaviour of alloys as a function of composition, and for computer-aided optimisation tools for alloy design. The project aimed at developing new predictive models, and at including them in computing tools for the design of new alloys for aeronautical, energy and chemical engineering applications. Optimisation can be made on several alloy properties simultaneously, using automatic computing tools called genetic algorithms. Such alloy design tools rely on a number of predictive models; we aimed at extending the range of predictive tools by developing several models.
Several models, already existing at the start of the project, have been used as some of the optimisation criteria for automatic alloy design (mechanical properties, among others). During the project, new models have been developed:
- Prediction of dynamic recrystallisation (DRX) of nickel-based superalloys. DRX is a metallurgical phenomenon that can be exploited to better control alloy processing (e.g. forging), and as a result the product quality and its final properties.
- Models linked to the resistance to hydrogen embrittlement (RHE) of nickel-based superalloys, or to their resistance to high temperature oxidation (RHTO); such models can be exploited to design alloys with improved resistance to environmental degradation.
- Prediction of the stability of so-called “high entropy alloys” (HEAs), a new class of materials with extraordinary combinations of properties (strength, density, ductility and corrosion resistance).
In the end, new alloys can been designed:
- New HEAs have been designed, fabricated and tested; some of them display unprecedented combinations of strength and density.
- New superalloys have been designed using the DRX model, with both an optimised behaviour under high temperature processing (e.g. forging) and maximum strength.
- New superalloys can be designed using the RHE or the RHTO models, with optimal resistances to environmental degradation along with excellent mechanical properties.
All developed models constitute a progress beyond the state of the art, by taking more microstructural complexity into account in the DRX model for superalloys, by computing explicitly the compositional dependence of environmental resistance of superalloys (RHE or RHTO), or by combining all previously existing criteria in a unified probabilistic model to evaluate the stability of HEAs. Regarding the potential impact of the project, some of the developed models and the alloy design strategy have raised the interest of several European aeronautical an energy companies.