by Fett, Theo; Creek, Dominic; Wagner, Susanne; Rizzi, Gabriele; Volkert, Cynthia A.

The validity of fracture toughness data obtained from tests with V-notched bending bars is affected by the notch root radius and the presence of R-curve behavior. A macroscopic test specimen has been developed that contains a notch introduced by focused ion beam machining. This produces a notch root radius of less than 0.1 μm, so that notch effects can be ignored for most ceramics. Also, due to the very small notch depths the influence of a rising R-curve should be very close to that of natural cracks. First tests, carried out on a Ce-doped zirconia ceramic resulted in a toughness of K
_Ic ≈ 5.9 MPa√m.

DOI: 10.1007/s10704-008-9288-1
Online Date: 12/5/2008
Print publication date: 9/1/2008
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