Formation Mechanisms of Microstructure Imperfections and their Effects on Strength in Submicron Cemented Carbide

摘要

The characteristics and formation mechanisms of microstructure imperfections in two sets of submicron WC-10％Co cemented carbides,which are fabricated b(y) vacuum and low-pressure sintering,respectively,is deeply analyzed.Main imperfections are pore-Co-pool in the vacuum-sintered samples.The number of pore-Co-pool is obviously reduced by low-pressure sintering,but many porous microstructures with poor-Co or Co-free are easily introduced; the impurities segregation is also easily formed.Transverse rupture strength (TRS) of samples is strongly affected by the characteristics and size of imperfections.Two linear relationships between TRS and pore size are experimentally established,and a critical pore size has been calculated to be 28.8 μm.