纳米晶W粉的制备及烧结性能

Preparation of Nanocrystalline Tungsten Powder and Study of Its Sinterability

用高能球磨法制取纳米晶W粉，在真空炉内将此W粉分别进行无压和热压烧结成致密块体。利用扫描电镜、透射电镜、X－ray衍射仪等观测球磨过程中粉末粒度、形貌和结构的变化以及烧结块体的质量密度随温度的变化，并与普通粉的烧结性能作了比较。结果表明：脆性材料在高能球磨过程中不出现片层状结构，一直保持颗粒状结构；纳米晶超细W粉与普通W粉相比，由于颗粒和晶粒小、扩散系数高、表面能高、比表面原子数多、晶格畸变严重、熔点低等使得烧结驱动力提高，物质迁移速率加快，其烧结性能大幅度提高。

Nano-crystalline tungsten powder prepared by high - energy ball milling was consolidated without pressure and with pressure, respectively. The change of the particle size and morphology, and the relative density of the sintering compact as a function of consolidation temperature has been studied by SEM, TEM and X - ray diffraction. The sinterability of nanocrystalline tungsten powder is compared with that of coarse - grained tungsten powder. It is found that the usual layered structure does not develop during the high - energy ball milling of brittle materials. This work demonstrates that the sinterability of nanocrystalline powder is far superior to that of a coarse - grained one.Correspondent: Chen Xianfeng, Candidate for Master Degree, State Key Laboratory for Mechanical Behavior of Materials, Xi'arl Jlao'tong University, Xi'an 710049, P. R. China, Tel: 086 - 29 - 3268912