钢中析出相场发射扫描电镜的自动统计分析技术研究

以往对析出相的研究均是通过透射电镜来获取析出相的成分、数量和尺寸等数据,难以实现析出相的自动统计分析。因此,为了实现自动统计分析,借助场发射扫描电镜(FE-SEM)与能谱分析软件Feature功能详细地研究了钢中析出相的自动统计分析技术,特别是对该方法中的样品制备、组织类型、析出相以及参数的设置与选择等主要影响因素进行了细致的分析。研究结果表明,实验最佳条件为采用化学侵蚀法、10000倍的放大倍数、阈值为110~255,总分析面积不超过0.1mm²。考虑到设备分辨率的影响,该实验方法只能对50nm以上的析出相进行统计分析,结合700L钢的实验结果可知,其析出相的种类有碳氮化钛和碳氮化钛与铌的复合析出,所占比例分别为58%和42%,50~200nm析出相数量较多。

Study on automatic statistical analysis technology of precipitated phases in steel by field emission scanning electron microscope

In previous studies of precipitated phases, the composition, quantity and size are usually obtained by transmission electron microscope (TEM), which is difficult to realize the automatic statistical analysis of precipitated phases. In order to achieve the automatic statistical analysis, the field emission scanning electron microscopy (FE-SEM) and feature function in energy spectrum analysis software were used to systemically study the precipitated phases in steel. Particularly, the main influencing factors in proposed method such as sample preparation, microstructure type, precipitated phases, setting and selection of parameters were analyzed in detail. The results indicated that the optimum experimental conditions were listed as follows:the chemical etching, magnification of 10000, threshold value of 110-255 and maximum total analysis area of 0.1mm². Considering the influence of instrument resolution, the proposed experimental method was only suitable for statistical analysis of precipitated phase larger than 50nm. According to the experimental results of 700L steel, the precipitated phase was composed of titanium carbonitride and titanium carbonitride-niobium carbonitride with proportion of 58% and 42%, respectively. The precipitated phases with size in range of 50-200nm were dominant.