(Ti,W)C-Ni金属陶瓷的显微组织和力学性能研究

Research on Microstructure and Mechanical Properties of(Ti,W)C-Ni Cermets

采用商用(Ti_(0.76),W_(0.24))C、(Ti_(0.69),W_(0.31))C、(Ti_(0.58),W_(0.42))C和Ni粉末,通过真空烧结制备了(Ti,W)C-Ni金属陶瓷。研究了(Ti,W)C中W含量对(Ti,W)C-Ni金属陶瓷显微组织和力学性能的影响。研究结果表明,(Ti,W)C-Ni金属陶瓷具有芯-环结构显微组织。随着W含量升高组织中芯相体积分数下降,环形相体积分数明显上升。当a(Ti)∶a(W)为0.69∶031时,金属陶瓷组织中出现了少量的无芯相,但进一步增加W含量,金属陶瓷中析出WC相和石墨相。较之传统的Ti(C,N)基金属陶瓷,(Ti_(0.69),W_(0.31))C-Ni金属陶瓷具有优异的断裂韧性(KIC),其数值为16.94 MPa·m^(1/2)。环形相与芯相的体积分数比例是影响(Ti,W)CNi金属陶瓷力学性能的关键因素。

The(Ti,W)C-Ni cermets were prepared by vacuum sintering with the commercial available(Ti0.76,W0.24)C,(Ti0.69,W0.31)C,(Ti0.58,W0.42)C and Ni powders. The effects of W content in(Ti,W)C on the microstructure and mechanical properties of the(Ti,W)C-Ni cermets were analyzed and evaluated. The results show that the(Ti,W)C-Ni cermets have a core-rim structure. The volume fraction of the core phase decreases and the volume fraction of the rim phase increases with the increase of W content. In addition, when the Ti/W atom ratio is 0.69∶0.31, a small amount of rimless(Ti,W)C phase occurs in the microstructure. However, the WC phase and graphite phase precipitates in the microstructure with further increase of W content. Compared with traditional Ti(C,N) cermets, the(Ti0.69,W0.31)C-Ni cermets have excellent fracture toughness(KIC) of16.94 MPa·m1/2. The volume fraction ratio of the rim phase and the core phase is a key factor impacting on the mechanical properties of the(Ti,W)C-Ni cermets.