原料液氮低温球磨处理对Ti-Al2O3复合材料力学性能的影响

摘要

针对Ti-Al2O3金属陶瓷烧结过程中易形成金属间化合物脆性相,从而劣化力学性能的问题,采用液氮低温球磨制备表面氮钝化的Ti纳米粉体,并进一步制备Ti-Al2O3复合材料,研究液氮球磨时间对Ti粉物相组成和微观结构的影响,并对比液氮球磨处理前、后粉体对Ti-Al2O3复合材料物相组成、微观结构及其力学性能的影响.结果表明,液氮低温球磨后的复合粉体明显改善了Ti-Al2O3复合材料的烧结情况,孔洞减少,致密性变好,物相分散均匀,并且液氮球磨后未发现Ti3Al脆性相,取而代之的是TiN和AlTi3N相,从而使Ti-Al2O3复合材料的强度和硬度显著增大.%To overcome the generation of brittle phase of inter-metallic compound during the sintering process of Ti-Al2O3 cermet and the decrease of mechanical properties of the composites,the surface nitrogen passivation of titanium nano-par-ticles were prepared by using a liquid nitrogen ball mill,and Ti-Al2O3composites were prepared further. The effect of liquid nitrogen milling time on the phase composition and microstructure of Ti powders were studied. The change of pha-ses,microstructures,and mechanical properties of sintered composites before and after cryomilled in liquid nitrogen were explored. The results show that the sintered Ti-Al2O3composites after ball milling of raw materials possess fewer pores, better compactness,and uniformly dispersed phases. Its bending strength and micro-hardness are significantly improved owning to the disappearance of Ti3Al brittle phase and the generation of TiN.