纯铁经表面机械研磨处理后微结构参量的表征

Characterization of Microstructural Parameters of Pure Iron after Surface Mechanical Attrition Treatment

用X射线线形分析法(XLPA)测定了经表面机械研磨处理(SMAT)后纯铁的有效晶粒(亚晶)尺寸、微观应变、位错密度和体弹性储能密度,用TEM观察了组织形貌,并与40%拉伸试样进行了对比。结果表明:纯铁经SMAT 90 min后,平均位错密度高达1.0×1016m-2,表面亚晶粒尺寸在7 nm左右;相对拉伸而言,SMAT对晶粒细化和引入微观应变的效果十分明显;XLPA法与TEM法得到的晶粒尺寸基本一致。

The microstructural features of pure iron after surface mechanical attrition treatment （SMAT）, such as effective grain （subgrain） size, micro-distortion, dislocation density and elastic stored energy density, were determined by the X-ray line profile analysis（XLPA）. The microstructure was observed by SEM and compared to tensile samples with 40% deformation. The results indicate that for pure iron sample prepared by SMAT for 90 min the average dislocation density was 1.0×10^16m-2 and the effective grain size was about 7 nm, which produced the most effective grain refinement and the greatest micro-distortion compared with the tensile sample. The grain sizes determined by XLPA and TEM methods were very close.