Ni_x(Ti_(0.6),W_(0.4))_4C系η相的Ni含量对碳化合成(Ti_(0.6),W_(0.4))C-18Ni金属陶瓷组织与性能的影响

Effects of Ni content of Ni_x(Ti_(0.6),W_(0.4))_4C-type η phase on the microstructure and properties of(Ti_(0.6),W_(0.4))C-18Ni cermets prepared by carbonization process

先采用高能活化–预烧结法合成TiC基金属陶瓷(Ti_(0.6),W_(0.4)_)_4C-xNi(x为质量分数,%。x=6,8,12,18)系η相粉末,然后再补碳烧结制备(Ti_(0.6),W_(0.4)_)C-18Ni金属陶瓷。分析不同Ni含量的η相粉末的形貌与物相组成,并进一步研究η相粉末的Ni含量对(Ti_(0.6),W_(0.4)_)C-18Ni金属陶瓷组织与力学性能的影响。结果表明,随(Ti_(0.6),W_(0.4)_)4C-x Ni粉末的Ni含量增加,η相逐渐由Ni_2W_4C向Ni_6W_6C转变;(Ti_(0.6),W_(0.4)_)4C-x Ni粉末的Ni含量增加有利于烧结过程中WC的析出,当x=12%时,析出颗粒状WC相,当Ni含量增加至18%时,颗粒状WC相转变为板条状,板条状WC相的析出可更有效地提高(Ti_(0.6),W_(0.4)_)4C-xNi金属陶瓷的抗弯强度和韧性。(Ti_(0.6),W_(0.4)_)C-18Ni金属陶瓷的抗弯强度和断裂韧性都随η相粉末的Ni含量增加而提高,当x=18%时,抗弯强度和断裂韧性分别为1 730MPa和15.8 MPa·m1/2。

（Ti0.6,W0.4）4C-18Ni cermets were prepared by carbonization of η phase powders synthesized by high-energy activation and pre-sintering mixture powders with a composition of （Ti0.6,W0.4）4C-xNi（x=6, 8, 12, 18 mass fraction）. The effects of initial Ni content on the morphology and phase composition of η phase were studied, and the effects of η phase composition on the microstructure and mechanical properties of cermets were also investigated. The results indicate that the form of η phase changes from Ni2W4C to Ni6W6C with increasing Ni content. The increase of Ni content is beneficial to the precipitation of WC phase. The granular WC phase precipitates when the Ni content is 12%, and then transforms to plate-like WC with increasing Ni content to 18%. The precipitation of plate-like WC phase can improve the transverse rupture strength （TRS） and toughness of TiC-based cermets. The TRS and toughness of the carbonized （Ti0.6,W0.4）C-18Ni cermets both increase with increasing Ni content. When the initial content of Ni is 18%, the TRS and toughness are 1 730 MPa and 15.8 MPa·m1/2, respectively.