Date of Award
12-2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Materials Science and Engineering
Committee Chair/Advisor
Enrique Martinez Saez
Committee Member
Dilpuneet Aidhy
Committee Member
John Ballato
Committee Member
Jianhua Tong
Committee Member
Marian Kennedy
Abstract
Fusion energy is one of the cleanest and most efficient energy sources for future power generation. However, the design of plasma-facing materials (PFMs) for fusion devices remains one of the major challenges. The conventional material, tungsten (W), suffers from radiation hardening and embrittlement caused by the formation and accumulation of irradiation defects, which change its microstructure and mechanical properties and shorten its lifetime. To overcome these problems, tungsten-based high-entropy alloys (HEAs) are explored as potential candidates for next-generation PFMs. HEAs usually consist of four or more principal elements, each with a concentration higher than 5 at.%. The background of fusion energy and PFMs is introduced in Chapters 1 and 2, and Chapter 3 explains in detail the computational methods used in this study. Monte Carlo simulations based on cluster-expansion Hamiltonians combined with density-functional-theory (DFT) calculations were used to predict the phase stability of W-based HEAs and guide alloy design. Chapter 4 investigates a wide compositional range of WTaCrV HEAs, and Chapter 5 studies the effect of small additions of Hf on this system. The irradiation behavior of pure tungsten is also examined to extend the understanding of defect evolution. Chapter 6 analyzes the effect of equibiaxial strain on the diffusion of W self-interstitial atoms and adatoms, and Chapter 7 discusses void absorption as an additional mechanism for edge dislocations to unpin from voids. These findings help clarify the defect behavior in tungsten and offer guidance for developing radiation-tolerant tungsten-based HEAs for fusion applications.
Recommended Citation
Sun, Bochuan, "Computational Study of Refractory Metals and Alloys for Fusion Application" (2025). All Dissertations. 4115.
https://open.clemson.edu/all_dissertations/4115