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通过低温球磨制备纳米晶7050合金粉体,利用电感耦合法(ICP)测定粉体化学成分,用扫描电镜(SEM)、X射线衍射(XRD)和透射电镜(TEM)等手段分析球磨过程中粉体的组织演化。结果表明:获得的纳米晶7050合金粉体杂质含量较低;球磨过程中粉体平均颗粒尺寸逐渐增大,分布范围宽化;粉体的晶粒尺寸在球磨过程中不断减小,经6h球磨后为34nm;微观应变先增大后减小;第二相在球磨过程中逐渐消失,最终全部过饱和固溶于基体中。位错胞演化机理(Evolution of dislocation cells)在球磨过程中对晶粒细化起主导作用,断裂冷焊机理(Fracture and cold welding)为辅助细化方式。
The nanocrystalline 7050 alloy powders were prepared by low temperature ball milling. The chemical compositions of the powders were determined by inductively coupled plasma (ICP) method. The powders were analyzed by SEM, XRD and TEM. The evolution of the body. The results show that the content of impurities in the nanocrystalline 7050 alloy powder is low, the average particle size of the powders increases and the distribution range is widened during the ball milling process, and the grain size of the powders decreases continuously during the ball milling. After 34nm; micro-strain first increased and then decreased; the second phase gradually disappeared in the milling process, and finally all supersaturated solid solution in the matrix. Evolution of dislocation cells plays a leading role in the grain refinement during ball milling. Fracture and cold welding is the auxiliary mode of refinement.