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以Ti,Al和TiC为原材料,用无压煅烧合成法制备三元化合物Ti_3AlC_2。详细讨论了煅烧温度和铝含量对多晶Ti_3AlC_2纯度的影响。利用X射线衍射仪、场发射扫描电镜和场发射透射电镜研究了粉末材料的组织结构、晶粒大小、层板厚度和选区电子衍射花样。结果表明1300℃是合成Ti_3AlC_2粉末的最佳煅烧温度,1:1.2:2是Ti/Al/TiC原材料的最佳摩尔比。用热压法制备了不同烧结温度下的Ti_3AlC_2块体试样,在1300℃热压制备的Ti_3AlC_2块体的相对密度可达99.9%,其维氏硬度和三点抗弯强度分别为5.7 GPa和630 MPa。通过场发射扫面电镜观察材料的断口形貌,进一步分析了Ti_3AlC_2块体材料的强化机理。
Using Ti, Al and TiC as raw materials, the ternary compound Ti_3AlC_2 was prepared by pressureless calcination. The effect of calcination temperature and aluminum content on the purity of polycrystalline Ti_3AlC_2 was discussed in detail. X-ray diffraction (XRD), field emission scanning electron microscopy (SEM) and field emission transmission electron microscopy (TEM) were used to investigate the microstructure, grain size, thickness and electron diffraction pattern. The results show that 1300 ℃ is the best calcination temperature for the synthesis of Ti_3AlC_2 powder, and 1: 1.2: 2 is the optimum molar ratio of Ti / Al / TiC raw material. Ti_3AlC_2 bulk samples with different sintering temperature were prepared by hot pressing. The relative density of Ti_3AlC_2 block prepared by hot pressing at 1300 ℃ was up to 99.9%, and its Vickers hardness and three-point bending strength were 5.7 GPa and 630 MPa. The surface morphology of the material was observed by field emission scanning electron microscopy, and the strengthening mechanism of Ti_3AlC_2 bulk material was further analyzed.