Crack tip dislocation activity in refractory high-entropy alloys

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

2 Scopus Citations
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Author(s)

  • Shuai Chen
  • Zachary H. Aitken
  • Subrahmanyam Pattamatta
  • Zhi Gen Yu
  • Peter K. Liaw
  • Yong-Wei Zhang

Detail(s)

Original languageEnglish
Article number108753
Journal / PublicationInternational Journal of Mechanical Sciences
Volume262
Online published15 Sept 2023
Publication statusPublished - 15 Jan 2024

Abstract

Dislocation activities play an important role in the deformation and failure of refractory high-entropy alloys (RHEAs). However, the impact of chemical short-range ordering (SRO) on dislocation activities at a crack tip in RHEAs remains unclear. Here, we investigate the effect of SRO on the dislocation nucleation, propagation, and reaction at a crack tip in a body-centered-cubic (BCC) MoTaTiWZr RHEA, using a combination of molecular dynamic simulations and Monte Carlo methods. Our results indicate that this RHEA is energetically favorable to form SRO, developing a pseudo-composite microstructure with low-energy clusters (LECs), medium-energy clusters (MECs), and high-energy clusters (HECs). The HECs at the crack tip are favorable sites for dislocation nucleation whereas the MECs surrounding the HECs function as a strong matrix to stabilize the weak HECs. At elevated temperatures, the HECs near the crack tip transform to severely distorted BCC and disordered structures, which can cause the breakup, absorption, and annihilation of emitted dislocations and nucleation of new dislocations. Our work reveals the interesting role of SRO in altering the dislocation activities at the crack tip of RHEAs and suggests alternative routes for designing superior RHEAs at both room and elevated temperatures. © 2023 Elsevier Ltd.

Research Area(s)

  • Dislocation annihilation, Dislocation breakup, Dislocation nucleation, Refractory high-entropy alloys, Short-range ordering

Citation Format(s)

Crack tip dislocation activity in refractory high-entropy alloys. / Chen, Shuai; Aitken, Zachary H.; Pattamatta, Subrahmanyam et al.
In: International Journal of Mechanical Sciences, Vol. 262, 108753, 15.01.2024.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review