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通过形貌观察和硬度测试研究了球磨纯铁中纳米铁素体的形成机制．结果表明，在球磨过程初期，纳米铁素体首先在球磨颗粒的表层区域形成并呈现层片状结构．扫描电镜（ＳＥＭ）、透射电镜（ＴＥＭ）和高分辨电镜（ＨＲＥＭ）观察表明、层片状纳米铁素体区与颗粒内部加工硬化区具有不同的微观结构，而且它们之间的界面十分明显．显微硬度测试表明，前者的硬度数值明显高于后者．进一步的球磨过程导致颗粒细化并完全转变为纳米铁素体．分析表明，纳米铁素体的形成是由于球磨过程中加工硬化效应产生的位错胞墙结构向晶界结构转变而导致的，这也是造成加工硬化区与纳米铁素体区之间存在硬度差异的原因．
The formation mechanism of nanometer ferrite in ball mill pure iron was studied by morphology observation and hardness test. The results show that in the early stage of ball milling, nano-ferrite is firstly formed in the surface layer of ball milling particles and has a lamellar structure. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) observations show that the lamellar nanoferritic region has different microstructures with the grain work-hardened region, and the interface between them is very clear. Microhardness test showed that the former hardness value was significantly higher than the latter. Further ball milling leads to grain refinement and complete conversion to nano-ferrite. The analysis shows that the formation of nano-ferrite is caused by the transformation of the dislocation cell wall structure to the grain boundary structure caused by the work-hardening effect during ball milling, which also results in the difference in hardness between the work hardening zone and the nano-ferrite zone s reason.