TiC对WC-13Co细晶粒硬质合金组织和性能的影响

Effect of titanium carbide on microstructure and properties of fine grain WC-13Co cemented carbides

以WC、TiC为硬质相,Co为粘结相,通过湿磨混粉、造粒、模压成形、气氛烧结制备硬质合金材料。通过X射线衍射、SEM、万能材料试验机等方法研究了TiC的添加量对细晶粒硬质合金组织和性能的影响。结果表明：添加TiC可以抑制W在Co中的固溶,提高合金的磁性钴含量;烧结过程中WC和TiC反应生成一种灰色的（Ti,W）C固溶体,具有较高的硬度,随着TiC含量的增加,合金的钴磁、硬度均升高而抗弯强度下降。在裂纹扩展过程中,（Ti,W）C固溶体可以使裂纹发生偏转,延长裂纹扩展路径,同时可以对裂纹起到钉扎作用,对合金有增韧作用。

Cemented carbide materials were prepared by mixing powders with alcohol, prilling, molding to shape and atmosphere sintering using WC and TiC as hard phase and Co as bonding phase. The effects of the amount of TiC on microstructure and properties of the fine grain cemented carbides were studied by means of XRD, SEM and universal material testing machine. The results show that the addition of TiC can inhibit the solid solution of tungsten in cobalt and improve the magnetic cobalt content of the cemented carbides. During the sintering process, WC and TiC react to produce a gray solid solution of （Ti,W）C with higher hardness. However, with the increasing of the amount of the TiC, the magnetic cobalt and the hardness of the cemented carbides increase while the bending strength decreases. In the process of crack propagation, （Ti,W）C solid solution can deflect the orientation of crack, prolong the path of crack propagation, and play a pinning action on the crack, which can toughen the cemented carbides.