热压原位合成TiC-xNi复合材料的组织与性能  

Microstructure and properties of in-situ TiC-xNi composites synthesized by hot-pressing

作　　者：包艳蓉[1] 刘宗德[1] 李斌[1] 

机构地区：[1]华北电力大学电站设备状态监测与控制教育部重点实验室,北京102206

出　　处：《金属热处理》2010年第1期37-42,共6页Heat Treatment of Metals

基　　金：国家自然科学基金(10772066);教育部创新团队项目(IRT0720)

摘　　要：以钛粉、石墨、钼粉和镍粉为原料,热压原位合成TiC-xNi复合材料。研究碳钛比及镍含量对热压原位合成TiC-xNi复合材料的组织和力学性能的影响。用扫描电镜和X射线衍射仪对复合材料的组织和物相组成进行分析,测试复合材料的致密度、硬度和抗弯强度。结果表明,热压原位合成的碳化物颗粒比较细小,尺寸为0.5-4μm。碳钛比及镍含量对最终产物的相组成没有影响。随碳钛比的增大（从0.9增大到1.0）,热压合成TiC-xNi复合材料的组织变得复杂,出现了亮环形组织、亮核/环形结构组织和灰核／环形结构组织，且碳化物颗粒和粘结相的边界平直化。随着镍含量的增加，复合材料的致密度、硬度和抗弯强度都有所降低，碳钛比对复合材料的致密度和硬度影响不大，但抗弯强度随碳钛比的增大明显减小。热压原位合成TiC—xNi复合材料的弯曲断口以沿晶断裂为主，40vol％TiC—Ni复合材料的断口中还出现了一些撕裂棱。TiC-xNi composites were in-situ synthesized by hot pressing from mixed titanium,graphite,molybdenum and nickel powders.The effects of carbon-titanium ratio and nickel content on microstructure and mechanical properties of TiC-xNi composites were investigated.Microstructure and phases composition of the composites were analyzed by scanning electron microscopy and X-ray diffraction respectively.Relative density,hardness and bending strength were measured.The results show that fine carbide grains with 0.5-4.0 μm are in-situ synthesized by hot pressing.The carbon-titanium ratio and the amount of nickel do not influence the presence of phases in the final products.As the carbon-titanium ratio increases（from 0.9 to 1.0）,the microstructure of TiC-xNi becomes complex with bright rims,bright core/rim structure and grey core/rim structure present,moreover,the boundary morphology between the carbide grains and the binder phases changes from an almost rounded shape to an angular shape.Furthermore,the increase of nickel content results in the decrease of relative density,hardness and bending strength.The carbon-titanium ratio has little effect on the relative density and hardness of the composites,while the bending strength decreases with increase of carbon-titanium ratio.The fracture surfaces of the composites are mainly intergranular fracture and some trace of tear ridges can also be found on the fracture surface of 40vol%TiC-Ni composites.

关 键 词：热压 原位合成 TiC-xNi复合材料 组织 力学性能 

分 类 号：TG148[一般工业技术—材料科学与工程]