纳米晶Mo-Cu复合粉末烧结行为的研究

Sintering Behavior of Nanocrystalline Mo-Cu Composite Powders

摘要:

采用溶胶-喷雾干燥-煅烧-氢气还原的方法制备了纳米晶Mo-18Cu、Mo-30Cu、Mo-40Cu复合粉末，研究了纳米晶Mo-Cu粉末的烧结行为以及Cu含量对致密化的影响。结果表明，纳米晶Mo-Cu复合粉末致密化程度高，速度快，在1050~1200 °C烧结，Mo-30Cu和Mo-40Cu的相对密度可达98%以上，且合金晶粒细小，而Mo-18Cu在1350 °C以上烧结，相对密度也可达98%以上，但晶粒聚集长大到5 μm左右。研究发现Mo-Cu复合粉末形成了亚稳态的超饱和Mo（Cu）固溶体，随着烧结温度的升高，Cu相逐渐从亚稳态的超饱和Mo（Cu）固溶体颗粒中析出。

Abstract:

Nanocrystalline Mo-18Cu, Mo-30Cu and Mo-40Cu (wt%) composite powders were fabricated by sol-spray drying, calcinating and subsequent hydrogen reduction process. The sintering behavior of nanocrystalline Mo-Cu composite powder and the influence of the copper content on the sintering densification process were investigated. The result shows that nanocrystalline Mo-Cu composite can obtain a fully dense structure. Particularly, Mo-30Cu and Mo-40Cu sintered at 1050-1200 °C can achieve relative densities over 98% and attain fine-grain structures. The relative density of Mo-18Cu sintered at 1350-1400 °C can also reach 98%, while a coarse structure with a mean grain size of 5 μm is obtained due to the remarkable grain growth in the compact. According to the compositional analysis, metastable Mo (Cu) solid solution forms in the composite powder. However, with the increase of the sintering temperature, Cu precipitates gradually from the metastable Mo (Cu) solid solution.