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在不同温度下采用真空烧结、X射线衍射(XRD)和背散射扫描电镜(BSE-SEM)研究了Ti(C_(0.7)N_(0.3))-WC-Mo_2C-TaC-Fe/Co/Ni体系金属陶瓷在烧结过程中的微观结构和相转变规律。研究结果表明,在1000℃以后WC相突然消失,显微组织中出现大量白色絮状析出相,其为固相烧结阶段形成与环形相成分相似的(W,Ti,Mo,Fe)C固溶体,并且大量的M_(12)C型η_2相存在于合金烧结体中。在1200℃以后Mo_2C,TaC和η_2相消失,随着温度的变化,合金中η相的种类及其含量发生变化。在1250℃以后M_(12)C型η相逐渐转变为M6N型脆性相,且高Fe含量粘结相的存在促进了M6N型脆性相的生成。在1410℃以后,原子扩散和溶解-析出过程更为充分,环形相厚度增加,且组织中析出了亮芯灰环结构,M_6N型脆性相减弱至逐渐消失,因此可以认为脆性相是在烧结的初期阶段形成但是随着烧结的进行而逐渐溶解消失。
The effects of Ti (C 0.7 Nb 0.3) -WC-Mo 2 C-TaC-Fe / Co / Ni system were investigated by vacuum sintering, X-ray diffraction and backscattering scanning electron microscopy (BSE- Microstructure and Phase Transformation of Cermet during Sintering. The results show that the WC phase abruptly disappears after 1000 ℃, and a large amount of white flocculent precipitates appear in the microstructure, which forms solid solution of (W, Ti, Mo, Fe) C similar to the annular phase in solid phase sintering. And a large number of M_ (12) C type η_2 phase exists in the alloy sintered body. After 1200 ℃, Mo 2 C, TaC and η 2 phase disappear. With the change of temperature, the type and content of η phase in the alloy changed. After 1250 ℃, the η phase of M_ (12) C gradually transformed into the M6N type brittle phase, and the existence of high Fe content binder phase promoted the formation of M6N type brittle phase. After 1410 ℃, the atomic diffusion and dissolution-precipitation processes are more complete, the thickness of the annular phase increases, and the bright gray-ring structure is precipitated in the microstructure. The M_6N-type brittle phase weakens until gradually disappears. Therefore, it can be considered that the brittle phase is in the sintered The initial stage was formed but gradually dissolved and disappeared as the sintering progressed.