Portevin-Le Chatelier mechanism in face-centered-cubic metallic alloys from low to high entropy

Che Wei Tsai, Chi Lee, Po Ting Lin, Xie Xie, Shuying Chen, Robert Carroll, Michael Leblanc, Braden A.W. Brinkman, Peter K. Liaw, Karin A. Dahmen, Jien Wei Yeh

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Abstract

Serration phenomena during tensile testing on certain alloys with diffusing solute atoms (i.e., Portevin-Le Chatelier effect) have been observed for a long time, but detailed mechanisms are not fully clear yet. This study is intended to find the mechanism from different approaches verified by tensile testing on a series of single-phase face-centered-cubic (FCC) pure metal and alloys: Ni, CoNi, CoFeNi, CoCrFeNi, and CoCrFeMnNi, which range from low to high configurational entropy. The results of tensile tests, at strain rates from 1 × 10-5 to 1 × 10-2/s and temperature from room temperature to 700 °C, show that serrations occur on stress-strain curves of CoFeNi, CoCrFeNi, and CoCrFeMnNi alloys in their specific temperature and strain-rate regime. A mechanism for dislocation pinning is proposed and verified with theoretical calculation for the present substitutional alloys. The proposed mechanism involves the in-situ rearrangement of substitutional solute atoms by "local dislocation-core diffusion" and might also be applied to similar substitutional alloys.

Original languageEnglish (US)
Pages (from-to)212-224
Number of pages13
JournalInternational journal of plasticity
Volume122
DOIs
StatePublished - Nov 2019

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Keywords

  • High-entropy alloy
  • Medium-entropy alloy
  • Portevin-Le Chatelier effect
  • Serration mechanism
  • Substitutional alloy

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Tsai, C. W., Lee, C., Lin, P. T., Xie, X., Chen, S., Carroll, R., Leblanc, M., Brinkman, B. A. W., Liaw, P. K., Dahmen, K. A., & Yeh, J. W. (2019). Portevin-Le Chatelier mechanism in face-centered-cubic metallic alloys from low to high entropy. International journal of plasticity, 122, 212-224. https://doi.org/10.1016/j.ijplas.2019.07.003