Four different shear test methods i.e. double-notched shear test, asymmetrical four point bend test, Iosipescu test, and torsion test, were investigated for their ability to evaluate one type of SiC-to-SiC brittle ceramic joint while using small-size specimens. The double-notched shear test showed higher stress concentration at the notch roots and a lower apparent shear strength. Both asymmetrical four point bend test and Iosipescu test utilized epoxy joined metal extensors, which failed during test and caused misalignment and tensile stress failures. The torsion test can deliver valid, single mode shear loading. However, failure in the SiC base material was observed for the torsion joint specimens in this study. None of the tests reliably induced true shear failure of the Ti_3SiC_2 MAX phase joint, because the joint is stronger and tougher than the SiC substrate. Torsion tests appear to be the most promising because of the pure shear loading, relatively low stress concentration, and easy alignment.
展开▼
