聚焦离子束扫描电镜三维重构夹杂物的形态和分布

Three-dimensional reconstruction of morphology and distribution of inclusions by focused ion beam-scanning electron microscope

以MnS易切削钢和EH36电渣焊焊缝区样品为研究对象,首先利用聚焦离子束扫描电镜的自动系列切片和成像(Auto Slice&View)功能对夹杂物进行逐层切片并成像,然后利用Amira软件根据夹杂物的衬度进行三维重构,从而得到钢铁材料中单一夹杂物及复合夹杂物的形态和分布。其中,复合夹杂物的物相确定还结合了电子探针的元素面分析和电子背散射衍射的物相分析功能。结果表明,MnS易切削钢中的夹杂物呈现条形体、纺锤形体和椭球形体共存的分布状态,而EH36电渣焊焊缝区的复合夹杂物主要由晶态Mn2TiO4相和富集Al、Ca、Mg、Si、Mn、O元素的非晶相组成,且两种相伴生存在。夹杂物的三维重构图清晰显示了夹杂物的形态和分布特征,对于研究夹杂物对钢材性能的影响提供了重要依据。

The MnS free-cutting steel and EH36 electroslag weld zone samples were selected as the research object for the study.The layer-by-layer sectioning and imaging of inclusions were firstly conducted using the Auto Slice&View functions of focused ion beam-scanning electron microscope(FIB-SEM).Then,the Amira software was used for three-dimensional reconstruction based on the contrast of inclusions to obtain the morphology and distribution of signal inclusion and composite inclusion in steel materials.The phase identification of composite inclusion also combined with the elemental mapping analysis function of electron probe micro-analyzer(EPMA)and phase analysis function of electron back scattering diffraction(EBSD).The results showed that the inclusions in MnS free-cutting steel showed the coexisting distribution of strip type,spindle shape and ellipsoidal type,while the composite inclusion in EH36 electroslag weld zone sample was mainly composed of crystalline Mn2TiO4 phase and amorphous phase with rich Al,Ca,Mg,Si,Mn and O.Moreover,these two phases were associated with each other.The three-dimensional reconstruction graph clearly showed the morphology and distribution characteristics of inclusions,which provided important basis to study the influence of inclusions on steel properties.