Abstract
In order to elucidate the effect of strain rate on high temperature deformation and fracture properties of cemented carbides, bend tests were carried out at 1000°C on WC-(6-20)%O Co alloys with several WC particle-sizes; the strain rates were varied by from 3 × 10-4 to 10-1/min. The results obtained are as follows:
(1) With the decrease of strain rate, the transverse rupture strength (T.R.S.) in general decreases whereas the fracture strain increases. (2) The drop of T.R.S. and the increase of fracture strain mentioned in (1) become more pronounced with decreasing WC particle-size and/or Co content. (3) At high strain rates (≥10-1/min), T.R.S. becomes a function of the contiguity of carbide particles; T.R.S. generally increases with increasing the contiguity. (4) The drop of T.R.S. with decreasing strain rate is inversely propational to the logarithm of mean free path of Co phase.
The mechanisms of the deformation and fracture of the alloy at 1000°C were discussed.
