Departing from the mutual exclusiveness of strength and ductility in nanocrystalline metals with vacancy induced plasticity

Journal Article · Mon Jul 30 00:00:00 EDT 2018 · Scripta Materialia

DOI:https://doi.org/10.1016/j.scriptamat.2018.07.037· OSTI ID:1483966

Islam, Zahabul ^[1]; Wang, Baoming ^[1]; Hattar, Khalid ^[2]; Gao, Huajian ^[3]; Haque, Aman ^[1]

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1. Pennsylvania State Univ., University Park, PA (United States). Mechanical & Nuclear Engineering
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
3. Brown Univ., Providence, RI (United States). School of Engineering

We report that strength and ductility are mutually exclusive in metallic materials. To break this relationship, we start with nanocrystalline Zirconium with very high strength and low ductility. We then ion irradiate the specimens to introduce vacancies, which promote diffusional plasticity without reducing strength. Mechanical tests inside the Transmission Electron Microscope reveal about 300% increase in plastic strain after self ion-irradiation. Molecular dynamics simulation showed that 4.3% increase in vacancies near the grain boundaries can result in about 60% increase in plastic strain. Finally, both experimental and computational results support our hypothesis that vacancies may enhance plasticity through higher atomic diffusivity at the grain boundaries.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• Grant/Contract Number: AC04-94AL85000; NA0003525; NE0008259
• OSTI ID: 1483966
• Alternate ID(s): OSTI ID: 22819307; OSTI ID: 1694088
• Report Number(s): SAND--2018-8772J; 666919
• Journal Information: Scripta Materialia, Journal Name: Scripta Materialia Journal Issue: C Vol. 157; ISSN 1359-6462
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
Ion irradiation
Molecular dynamics
Nanocrystalline metals
Nanoscale plasticity
Vacancy diffusion