机械合金化Mo-Cu粉末的烧结特性

Sintering characteristics of mechanically alloyed Mo-Cu powder

采用高能球磨方法制备了超细Mo—Cu复合粉末，通过X射线衍射，金相显微镜，扫描电镜和透射电镜等方法研究分析了所制备Mo-Cu粉末的烧结致密化、显微组织及性能的变化，并与未球磨粉末的烧结试样进行了比较。结果表明：经机械合金化的Mo-Cu粉末处于非平衡储能状态，烧结活性较高，使致密化温度降低80～100℃；其成形压坯在1250℃下烧结1．5h后，性能较佳，相对密度达到97．9％，且烧结体Mo、Cu两相分布均匀，其硬度、电导率、热导率分别达到70．10HRB、23．17ms／m、179．33W／（m·K），与未球磨粉末烧结体性能相比，都有了显著提高；过高的烧结温度与过长烧结时间，会引起Mo晶粒的明显长大。

The Mo-Cu Composite powder was prepared by high energy bailing, and the sintering densification behavior and evolution of microstructure and properties of the mechanically alloyed Mo-Cu composite powder in the process of sintering were studied by optical microscope, XRD, SEM and TEM. The experimental result was compared with that of sample sintered with the mixed Mo-Cu powder without high energy ball milling. The result shows that the Mo-Cu composite powder after high energy ball milling is in a inequilibrium high energy state and exhibits high sintering reactivity, decreasing sintering temperature for 80 - 100℃. A relative density of 97.9% of the theoretical density and microstructure with homogeneously distributed Mo particles are obtained for the composite Mo-Cu compact sintered at 1250℃ for 1 .5h. The hardness, electrical and thermal conductivity of the sintered Mo-Cu composite are improved significantly compared with that of the sample prepared with the mixed Mo- Cu powder without high energy bailing, which are 70.10HRB, 23.17 ms/m, 179.33W/（m·K）, respectively. The increase of sintering temperature and time results in growth of Mo particles.