Mode I fracture toughness of SiC particle-dispersed ZrB_2 matrix composite measured using DCDC specimen

摘要

Mode I fracture toughness of SiC particle-dispersed ZrB_2 matrix composite has been measured using DCDC specimen. Compression test results of the DCDC specimen show that the fracture toughness of the composite is independent of crack length with an average toughness approx 3.5 MPa sqroot. Optical microscope and SEM observations reveal a flat crack path and fracture surface with no significant toughening mechanisms in the composite either through grain boundary deflection or SiC particle introduction. Comparison with previous ZrB_2 matrix composites, in addition to other short crack test methods, there is an agreement with the results between what this study has come upon with respect to previous work.