Tensile testing of ceramic fibres by video extensometry

A computer-assisted video extensometer was used to measure the Young's modu lus and tensile strength of commercially available alumina fibres (11.5 mu m in diameter). The results showed excellent agreement with manufacturers r eported values (384 +/- 12 GPa and 3132 +/- 296 MPa for Young's modulus and tensile strength, respectively). The machine was initially tested with 100 mu m diameter SiC monofilaments to identify optimum experimental condition s. The mechanical properties of these fibres were independent of the crossh ead speed and fibre length. This non-contacting extension measuring system allowed testing of fragile materials and a submicron resolution could be ac hieved with a high-precision CCD camera. The results in term of precision a nd resolution therefore meet the requirements for strain measurements in me chanical ceramic materials testing. (C) 2000 Kluwer Academic Publishers.