Fracture Toughness Characterization of Carbon Bonded Alumina Using Chevron Notched Specimens

E-ISSN： 1662-9795|2017|754|71-74

ISSN： 1013-9826

Source： Key Engineering Materials, Vol.2017, Iss.754, 2017-10, pp. : 71-74

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Abstract

A new generation of multifunctional filters is made of carbon bonded alumina and is investigated within the collaborative research center 920 (CRC920). These filters are used during a casting process with the aim of reducing non-metallic inclusions in the cast product. The high thermal and mechanical loading of the filter requires a fracture mechanical characterization of the investigated ceramic material.In order to determine the fracture toughness of the ceramic material, a chevron-notched beam method (CNB) is applied. A 4-point-bending test set-up was constructed and brought into service, at which the load-displacement curve of small chevron-notched specimens (5 x 6 x 25 mm³) can be measured. The set-up offers the possibility of testing specimens at temperatures up to 1000oC.Preceding numerically work using the finite element method was performed to identify a suitable notch geometry. For this purpose a cohesive zone model was used. A parameter study is presented, which shows the influence of the notch parameter on the load-displacement curve.