机械合金化对Cr-W粉末及烧结材料组织的影响

Influence of Mechanical Alloying on Microstructure of Cr-W Powder and Its Sintered Alloy

摘要:

通过机械球磨法制备原子比为4:1的Cr-W预合金粉末，对球磨后的Cr-W粉末进行XRD、SEM、TEM分析，探讨球磨时间对Cr-W粉末形貌、晶粒大小、组织结构及烧结Cr-W合金固溶度的影响。结果表明：采用机械合金化法，可以制备纳米级的Cr-W预合金粉末；球磨初期，晶粒尺寸、微应变变化较大，48 h后趋于稳定获得小于30 nm的纳米晶粉末；经72 h球磨后，粉末中有固溶体形成；球磨过程伴随着晶格常数的变化；球磨时间越长的粉末，烧结后各相分布越均匀，固溶程度越高

Abstract:

Cr-W pre-alloyed powders with the atomic ratio of 4:1 were prepared by mechanical milling using chromium and tungsten powder as raw material. The prepared powders were analyzed by XRD, SEM and TEM. The influence of ball milling time on morphology, microstructure and grain size of Cr-W pre-alloyed powders as well as compactness and solid solubility of the sintered Cr-W alloy were discussed. The results show that nanoscale Cr-W pre-alloyed powder can be prepared by mechanical alloying. At the initial stage of ball milling, the change of grain size and microstrain is very distinct; but it becomes a steady sate after milling for 48 h and at the same time the Cr-W pre-alloyed powders with nanocrystalline size of about 30 nm are obtained. After ball milling for 72 h, there is solid solution formed in the chromium and tungsten pre-alloyed powders. Lattice constants change during the milling process. For longer milling time of the powders, the more uniform distribution of each phase and the higher solubility are obtained after sintering