Cyclic Thermal Shock Tests of Cermets and Cemented Carbides

Abstract

Cyclic thermal shock tests were performed on cermets and cemented carbides by heating specimens in a furnace and plunging them into a water bath. The results thus obtained are summarized as follows : (1) The bending strength for the specimens of the cemented carbides subjected to the single thermal shock was larger than those of cermets, while in the cyclic thermal shock tests, the reverse tendency was observed especially in the tests performed at a low temperature difference. (2) In the cyclic thermal shock tests of the cemented carbides, many small cracks were initiated more easily than in cermets at the interface between WC and Co. A remarkable decrease of the bending strength of the cemented carbides subjected to the cyclic thermal shock may be caused by the large cracks formed by the coalescences among these numerous small cracks.