Abstract
The transverse-rupture strength of conventional WC-10%Co high carbon two-phase alloys (mean grain size is about 1.4μ) was measured as a function of width (w) or thickness (t) of the specimen. Then, the observed strength was examined in relation to the structural defects which appeared on the fracture surfaces as a fracture source.
Results obtained were as follows. (1) The increase of w or t resulted in the decrease of strength, showing the so-called volume effect. (2) The strength decrease was accompanied by the increase of the average defect (or source) dimension, and by that of the average distances from the tension surface and also from the span center to the defect. It was also accompanied by the change in the sort of defects. Thus, the volume effect as above was considered not to be simply related to usually cited risky volume, but to be related to the volume containing a defect which actually acts as a fracture source. (3) The effect of specimen-volume on the strength of conventional cemented carbide could not be satisfactorily explained by Weibull's equation.
