Fracture toughness of zirconia with a nanometer size notch fabricated using focused ion beam milling.
J Biomed Mater Res B Appl Biomater
; 108(8): 3323-3330, 2020 11.
Article
en En
| MEDLINE
| ID: mdl-32562464
ABSTRACT
OBJECTIVES:
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.METHODS:
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.RESULTS:
The FIB-notched specimens show a much reduced average fracture toughness of 5.64 ± 1.14 MPaâm compared to 8.90 ± 0.23 MPaâm 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.SIGNIFICANCE:
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 MPaâm, smaller than the specimens with V-notches fabricated using saw blades.Palabras clave
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MEDLINE
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Idioma:
En
Revista:
J Biomed Mater Res B Appl Biomater
Asunto de la revista:
ENGENHARIA BIOMEDICA
Año:
2020
Tipo del documento:
Article
País de afiliación:
Estados Unidos