Study on the relation between structural parameters and fracture strength of WC-Co cemented carbides

In this article, a directly proportional relation between average free path (M) and ductile deformation energy (y) was proposed, and on the basis of i t, a quantitative analysis was conducted for studying the effects of the st ructural parameters on fracture strength of WC-Co cemented carbides. The re sults show that, for different WC-Co cemented carbides with different cobal t contents, there exist different critical WC grain size R-c and critical f ree path of binder M-c. R-c and M-c act as the criteria that determine the growth behavior of crackles. When average free path of cobalt binder M < M- c, or WC grain size R < R-c, crackles will expand mainly across cobalt bind er, which will result in intergranular fracture; when M > M-c or R > R-c, t ransgranular fracture will happen; when M = M-c or R = R-c, concurrence of intergranular fracture and transgranular fracture will take place. R-c and M-c will decrease with increasing of cobalt content, followed by increasing of fracture strength. The dimension of crackles in the circular fissure-br eeding district is also a determinative factor to affect fracture strength of cemented carbides. (C) 2000 Elsevier Science S.A. All rights reserved.