Fracture toughness testing of small ceramic discs and plates

Mechanical properties of tape casted Lanthanum Tungstate for membrane substrate application

“…The biaxial tensile strength was determined by the B3B testing method. Details on the configuration as well as the evaluation procedure are explained in detail elsewhere [ 41,42,44 ].…”

XFEM investigation on Knoop indentation cracking: Fracture toughness and aspect-ratio of radial-median cracks

“…Marshall [10] performed Knoop microindentation cracking tests on hot pressed Si 3 N 4 (NC132); Lube [12] used a tougher silicon nitride, namely gas pressure sintered Si 3 N 4 doped with ≈ 3 wt.% MgO, and provided detailed crack dimensions; and Petrovic [11] performed Knoop indentation cracking tests on a common glass ceramic (C9606). Regarding the values for E, H (hardness) and K c , the materials cover quite a large range of brittle materials (Table 1).…”

“…(ii) The crack initiates as an enclosed median crack, which means that crack initiation is not affected by surface roughness. (iii) The prolate semi-spheroidal plastic zone is shallow, which makes Knoop indentation the preferred method for the surface crack in flexure (SCF) or similar techniques [9,10]. Further, obtuse indenters are less susceptible to tip blunting.…”

A Fracture Toughness Test Using the Ball‐on‐Three‐Balls Test

“…In material development or situations where ceramics are prepared on laboratory scale (e.g., by various pressing routes), a convenient specimen shape is a rather thin cylindrical disk. There also exist ceramic components such as resistors, watch glasses, and others which are disk‐shaped. This shape is also the prescribed form for biaxial strength tests of bio‐ceramics .…”

“…In Strobl et al it was already shown, that the B3B test is also a good basis for fracture toughness testing. Similar to the surface‐crack‐in‐flexure (SCF) method for bend bars a sharp semielliptical surface crack was introduced into a B3B specimen.…”