基于机械诱发自蔓延反应制备TiC基金属陶瓷的组织与性能

以Ti、Mo、C、Ni粉末为原料在氩气保护下通过高能球磨诱发的自蔓延燃烧反应合成了TiC-Ni和(Ti,Mo)C-Ni复合粉末,将合成的粉末经成形和烧结后制备得到了高韧性的金属陶瓷材料,并对碳化物的形成机理以及金属陶瓷的显微组织与力学性能进行了研究。结果表明:高能球磨诱发的自蔓延燃烧反应释放的热量造成了金属Ni熔化产生液相,Ti、Mo、C不断溶解于液相并发生反应,生成的TiC或(Ti,Mo)C在液相中形成并析出;制备得到的TiC-Ni和(Ti,Mo)C-Ni金属陶瓷易于烧结致密化,其硬度不低于13.2 GPa,弯曲强度不低于1 559 MPa,与传统粉末冶金方法制备的金属陶瓷相当,但是其断裂韧性高于传统金属陶瓷,可达12.04 MPa·m1/2。

Microstructure and Mechanical Properties of TiC-based Cermets Prepared by Mechanically Induced Self-sustained Reaction

TiC-Ni and （Ti,Mo）C-Ni composite powders were prepared by mechanically induced self-sustained reaction through high-energy ball milling of elemental powders of Ti, Mo, C and Ni under argon atmosphere, and thesynthesized composite powders were then pressed and sintered to prepare cermets. The formation mechanism of the carbides and the mierostrueture and mechanical properties of the eermets were also investigated. The results show that, the high-energy ball milling induces self-sustained combustion reaction, the tremendous heat released by the reaction melts metal Ni, then Ti, Mo and C dissolves and reactes in the liquid phase. Finally, TiC and （Ti,Mo）C formed in the liquid phase are precipitated out. TiC-Ni and （Ti,Mo）C-Ni cermets prepared by the composite powders are easily sintered to obtain full density materials, the hardness and bending strength of the materials is no less than 13.2 GPa and 1 559 MPa, separately, which are comparable with that of conventionally powder metallurgy produced cermets. The toughness of the cermet is as high as 12.04 MPa-mw, which is superior to that of conventionally produced cermets.