Predicting the Ductility of Tungsten Based BCC Refractory High Entropy Alloys: A Computational Science Driven Study

Author

Akshay Korpe, Clemson UniversityFollow

Date of Award

8-2024

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical Engineering

Committee Chair/Advisor

Enrique Martinez Saez

Committee Member

Garrett Pataky

Committee Member

Cheng Sun

Abstract

Bcc refractory high entropy alloys (HEAs) are a relatively new category of metallic alloys that promise excellent irradiation resistance and strength retention at high temperatures but exhibit brittle behavior at room temperatures limiting their formability. Understanding the deformation mechanisms and predicting their ductility at room temperature is a topic of interest in contemporary research.

In this work, multiple independent ductility criteria for quantifying the ductility of these HEAs were studied, calculated and compared using Density Functional Theory (DFT) calculations and continuum mechanics frameworks. These ductility parameters were calculated for various W-Ta-Cr-V alloys and the trends were analyzed for each criteria for dependence on the concentrations of the alloying elements.

The correlations between the analytical Rice model with the other approximate and phenomenological models were analyzed to investigate their viability to serve as computationally inexpensive surrogate models for screening potentially ductile HEAs from a large compositional space without performing DFT intensive computations required by the Rice model.

In order to further improve computational efficiency, a predictive cluster expansion model was developed using the DFT datasets generated for the W-Ta-Cr-V alloys to predict the Ground state energies of the HEAs. This framework is discussed for viability in accurately predicting the Free Surface Energies (ƔSURF) , Unstable Stacking Fault Energies (ƔUSF) and elastic constants, and by extension, the ductility of these alloys.

Recommended Citation

Korpe, Akshay, "Predicting the Ductility of Tungsten Based BCC Refractory High Entropy Alloys: A Computational Science Driven Study" (2024). All Theses. 4363.
https://open.clemson.edu/all_theses/4363