Fracture toughness of zirconia with a nanometer size notch fabricated using focused ion beam milling

Journal Article · 19 June 2020 · Journal of Biomedical Materials Research - Part B: Applied Biomaterials

DOI: https://doi.org/10.1002/jbm.b.34668 · OSTI ID:1646613

Liao, Yifeng ^[1]; Gruber, Max ^[1]; Lukic, Henry ^[1]; Chen, Si ^[2]; Megremis, Spiro ^[1]

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1. American Dental Association Science & Research Inst., Chicago, IL (United States)
2. Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source

Zirconia with 3 mol% yttria (3Y-TZP) has been used for dental crowns and bridges due to its excellent mechanical behavior. Performing fracture toughness testing on this nanograin material, however, can be a challenge. For reliable results, fracture toughness testing requires an extremely sharp notch in the test specimen that closely approximates a very sharp crack. This study was to investigate an alternative method to produce nanometer-sized notches, which are less than the average grain size of 3Y-TZP, during the preparation of single-edge V-notched beam specimens and report the resulting fracture toughness value. We present a method using focused ion beam (FIB) milling to fabricate nanometer-sized notches in 3Y-TZP. The notch tip is <100 nm wide, which is smaller than the grain size, and is consistent throughout the thickness of the specimen. The FIB-notched specimens show a much reduced average fracture toughness of 5.64 ± 1.14 MPa√m compared to 8.90 ± 0.23 MPa√m for the specimens without FIB-notches. The FIB-milling did not appear to create any monoclinic phase prior to fracture toughness testing. Fractures originated at the FIB-notches, and the notch size can be readily identified post-mortem using a microscope. A considerable amount of tetragonal-to-monoclinic phase transformation was observed throughout the fracture surfaces. FIB milling provides an alternative method to fabricate nanometer-sized notches that are smaller than the grain size of tetragonal zirconia polycrystal. The fracture toughness determined using FIB-notches was ~5.64 MPa√m, smaller than the specimens with V-notches fabricated using saw blades.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1646613
• Alternate ID(s): OSTI ID: 1756425
• Journal Information: Journal of Biomedical Materials Research - Part B: Applied Biomaterials, Journal Name: Journal of Biomedical Materials Research - Part B: Applied Biomaterials Journal Issue: 8 Vol. 108; ISSN 1552-4973
• Publisher: WileyCopyright Statement
• Country of Publication: United States
• Language: English