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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。
Titanium powder, graphite, molybdenum powder and nickel powder as raw materials, hot-pressed in-situ synthesis of TiC-xNi composites. The effects of carbon-titanium ratio and nickel content on the microstructure and mechanical properties of in-situ TiC-xNi composites were investigated. The microstructure and phase composition of the composites were analyzed by scanning electron microscopy and X-ray diffraction. The densification, hardness and flexural strength of the composites were tested. The results show that hot pressing in situ synthesis of carbide particles relatively small size of 0.5 ~ 4μm. The carbon-titanium ratio and the nickel content have no effect on the phase composition of the final product. With the increase of the ratio of carbon to titanium (from 0.9 to 1.0), the microstructure of TiC-xNi composites synthesized by hot pressing becomes complicated, and the bright ring, bright core / ring structure and gray core / ring structure appear. And the boundaries between the carbide particles and the binder phase are straightened. With the increase of nickel content, the densification, hardness and flexural strength of the composites decreased. The carbon-titanium ratio had little effect on the densification and hardness of the composites, but the flexural strength increased with the increase of carbon-titanium ratio Decrease The fracture of TiC-xNi composites in hot-pressed in-situ was mainly along the intergranular fracture, and some tearing edges appeared in the fracture of the 40vol% TiC-Ni composite.