活化烧结制备TiC-Ni金属陶瓷复合材料及其性能

Properties of TiC-Ni Cermets with Vacuum Active Sintering

采用球磨法制备TiC Ni金属陶瓷复合材料粉末 ,粉末在 30 0 0kg cm2 压力下压制成形 ,在 1340℃进行真空液相烧结。对活化粉末进行XRD分析和TEM分析 ,采用普通金相显微镜对烧结体的微观组织进行分析 ,用三点弯曲试验测试其抗弯强度 ,在硬度测试仪上测试其硬度。结果表明 :TiC Ni金属陶瓷复合材料可在 1340℃进行烧结制备 ,球磨初期粉末烧结体的微观组织随着粉体球磨时间的延长逐渐得到改善 ;过分延长球磨时间 ,则由于粉末中引入大量的缺陷和严重加工硬化而导致粉末压缩性能下降 ,进而抑制了材料的烧结致密化能力 ,使得烧结体的孔隙率急剧上升 ,力学性能相应下降。

Mechanical milling was employed to produce TiC-Ni cermets powder. Specimens pressed under 300MPa were sintered in a vacuum and in the presence of a liquid phase, at 1340℃.Microstructures of the active powder and sintered samples under different milling time were observed by XRD, TEM and optical microscope, respectively. Flexural strenghth and hardness of the sintered samples were tested. It was confirmed that through mechanical activation the sintering temperature was reduced to 1340℃ and the microstructure of the sintered sample was improved gradually with milling time at the initial period of milling. If the milling time is too long, the powders will be induced excessive defects and serious work hardening which leads to decreasing compressing ability. Consequently the densification ability was restrained, which leads to increasing porosity and bad mechanical property.