TiCx-VC系PCD结合剂的高温高压烧结

发布时间：2018-05-07 04:00

  本文选题：机械合金化 + 非化学计量比碳化钛　； 参考：《燕山大学》2015年硕士论文

【摘要】：以Ti粉和Ti C粉为初始原料,采用机械合金化(MA)法合成非化学计量比Ti CX(x=0.4、0.5、0.6),然后将其和VC按一定比例进行配混,在高温高压条件下进行烧结,压力保持恒定的5.0GPa,调整烧结温度和保温时间,研究烧结工艺参数以及非化学计量化合物Ti Cx中不同的C含量对烧结后试样结构和性能的影响。首先将Ti C0.4与VC进行分层叠烧,在扫描电镜下,借助于EDS技术分析二者界面附件各元素的分布,讨论界面处各种元素原子的扩散行为,由此判断VC中的C原子是否可以扩散进入到Ti Cx的空位中;其次研究Ti C0.4和VC的混合粉体的烧结,测定烧结体的维氏硬度和断裂韧性,通过SEM观察分析烧结体断口形貌,获得的最佳结合剂配方为Ti C0.4的体积分数为70%,VC的体积分数为30%,烧结温度为1500℃,烧结样品的维氏硬度为22.5GPa,断裂韧性值为3.69MPa·m1/2;当烧结温度为1600℃时,样品出现过烧现象;再次研究Ti Cx中不同C含量,即x取不同值时,以及保温时间不同对Ti Cx/VC烧结体性能的影响。将烧结温度选定在1450℃、1500℃、1550℃三个温度,x分别为0.4、0.5、0.6时,其高温保温时间分别为5min、10min、15min时,测定Ti Cx/VC烧结体的硬度和断裂韧性,对烧结后样品进行X射线衍射分析,确定其物相构成;并观察其断口形貌,找到x值对烧结行为的影响以及烧结保温时间对性能的影响。实验结果表明,Ti C0.5/VC烧结体在保温15min,烧结温度为1500℃时,硬度值达到最大为21.13GPa,韧性值为3.87 MPa·m1/2,Ti C0.6/VC烧结体在保温15min,烧结温度为1400℃时,硬度值最大,最大值22.24GPa,韧性值为3.73 MPa·m1/2。对于不同x值的Ti Cx/VC烧结体,随着x值增大,样品完全烧结所需要的保温时间逐渐缩短。
[Abstract]:Using Ti powder and tic powder as initial raw materials, the non-stoichiometric ratio of Ti CXX XN 0.4U 0.5N 0.6 was synthesized by mechanical alloying (MA) method, and then mixed with VC in a certain proportion and sintered under high temperature and high pressure. The influence of sintering process parameters and different C content in nonstoichiometric compound TiCx on the structure and properties of the sintered samples was studied by adjusting sintering temperature and holding time with constant pressure of 5.0 GPA. Firstly, TiC0.4 and VC were laminated and superimposed. The distribution of elements in the interface between them was analyzed by means of EDS technique, and the diffusion behavior of various elements at the interface was discussed. It is concluded that the C atom in VC can diffuse into the vacancy of TiCx. Secondly, the sintering of the mixed powder of TiC0.4 and VC is studied, the Vickers hardness and fracture toughness of the sintered body are measured, and the fracture morphology of the sintered body is observed and analyzed by SEM. The optimum formulation of the binder is: the volume fraction of TiC0.4 is 70%, the volume fraction of VC is 30, the sintering temperature is 1500 鈩，

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