Characterizations of WC-10Co nanocomposite powders and subsequently sinterhip sintered cemented carbide

摘要

Ultrafine WC-Co cemented carbides, combining high hardness and high toughness, are expected to find broad applications. In this study, WC-10Co-0.4VC-0.4Cr_3C_2 (wt. percent) nanocomposite powders, whose average grain size was about 30 nm, were fabricated by spray pyrolysis-continuous reduction and carbonization technology. The as-prepared nanocomposite powders were characterized and analyzed by chemical methods, scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET analysis and atomic force microscopy (AFM). Furthermore, "sinterhip" was used in the sintering process, by which ultrafine WC-10Co cemented carbides with an average grain size of 240 nm were prepared. The material exhibited high Rockwell A hardness of HRA 92.8, Vickers hardness HV_1 1918, and transverse rapture strength (TRS) of 3780 MPa. The homogeneously dispersed grain growth inhibitors such as VC, Cr_3C_2 in nanocomposite powder and the special nonmetal-metal nanocomposite structure of WC-10Co nanocomposite powder played very important roles in obtaining ultrafine WC-0Co cemented carbide with the desired properties and microstructure. There was an abundance of triple junctions in the ultrafine WC-10Co cemented carbide; these triple junctions endowed the sintered specimen with high mechanical properties.