微波烧结原位合成(Ti_5Si_3+TiC)/TC4复合材料组织性能研究

Microstructure and Properties of Microwave Sintering in situ Synthesis(Ti_5Si_3+TiC)/TC4 Composites

通过Ti-SiC反应体系,选择粒径为45μm的基体TC4,5μm的增强相SiC(质量分数为5%和10%),经过低能球磨混粉后,微波烧结原位合成颗粒增强钛基复合材料。采用X射线衍射仪(XRD)、扫描电镜(SEM)和能谱仪(EDS)对制备的钛基复合材料进行组织结构分析,并对钛基复合材料的致密度、显微硬度、压缩强度、抗拉强度、耐磨性和抗氧化性进行测试研究。结果表明,钛基复合材料主要由增强相TiC,Ti_5Si_3及基体Ti_3种物相组成。TiC呈颗粒状,有明显的棱角,而Ti_5Si_3呈熔融状颗粒,但是颗粒没有明显的棱角,增强相呈准连续网状分布,随着SiC含量的增加,网状结构不清晰,部分增强相团聚在一起。复合材料的相对密度、显微硬度和压缩强度随SiC含量的增加而增加,分别达到98.76%,HV729和2058MPa,但是复合材料的室温拉伸强度随SiC含量增加而降低。引入增强相后,复合材料的抗氧化性和耐磨性均高于基体,且耐磨性和抗氧化性随SiC含量增加而增加,其室温磨损机制主要为粘着磨损。

The particulate reinforced titanium matrix composites were synthesized in situ by microwave sintering through the Ti-SiC reaction system, in which the TC4 particle with the size of 45 μm as the matrix and the SiC （5% and 10% , mass fraction） of 5μm as the reinforcement phase were mixed by low energy ball mill. The X-ray diffraction （XRD）, Environmental scanning electron micro- scope（SEM） and energy dispersive spectrometer（EDS） were employed to analyze the microstructure of the composites. In the same time, the relative density, microhardness, compressive strength, tensile strength, wear resistance and oxidation resistance of the titani- um matrix composites were also investigated. The results showed that the titanium matrix composites were composed of TiC, Tis Si3 and Ti phases. The TiC exhibited granular with clear edges and comers. The Tis Si3 exhibited the molten particles, having no edge and cor- ner. The reinforced phase presented quasi-continuous mesh distribution, and the network structure turned foggy and agglomeration was observed from some reinforcement phase with the SiC contents increasing. The relative density, microhardness and compressive strength of the composites all increased with the SiC contents increasing, and reached 98.76%, HV 729 and 2058 MPa, respectively. But the tensile strength of the composites decreased with the SiC contents increasing at room temperature. The introduction of the reinforced phases increased the oxidation resistance and wear resistance of TC4 substrate, and increased with the SiC contents increasing. The wear mechanism of composite materials mainly referred to adhesive wear in normal temperature.