抄録
In order to elucidate the effect of residual pores and anomalously large WC particles on fracture properties of cemented carbides at elevated temperatures, the bend tests were carried out on WC-10% Co alloys with these defects of various sizes. The results obtained are as follows. (1) The influence of the residual pores on the fracture properties gradually vanishes with the rise of temperature, especially above 700°C. At high temperatures near 1000°C, even when the size of the residual pores exceeds 100μ, transverse rupture strength (refered to as T. R. S.) becomes to be unaffected with the existence of such defects. (2) With the rise of temperature, the mode of fracture at the fracture origin of the alloy containing anomalously large WC particles changes from a transgranular to intergranular type. This change of fracture mode occurs in the temperature range of 400 to 800°C depending on the defect size. (3) With decrease of strain rate, the transition temperature at which the residual pores have no effect on T. R. S., shifts to the lower temperature.
