Electron detection modes comparison for quantification of secondary phases of Inconel 686 weld metal

Quantitative analyses produce important information concerning the microstructural characteristics of materials, which are reflected in the main properties of the materials. The secondary and backscattered electron modes represent the two main techniques most used in scanning electron microscopy, to produce images and, consequently, realize a quantitative analysis. However, each technique has its advantages and problems. The present work proposed evaluate what is the best SEM technique to quantify secondary phases in a cladding of Inconel 686, which can be extended to the other classes of nickel based alloys rich in Mo. It was performed a quantitative analysis of several images to characterize the microstructure of Inconel 686 weld cladding. The images were obtained using three modes: secondary electron (SE), Z contrast backscattered electron (BSE) and topographic backscattered electron (BSE). The segmentation and quantify of secondary phases was performed by SVRNA software. The statistical results revealed differences between the techniques. The secondary electron mode included several artefacts that reduced the precision of the quantification study. The BSE modes are shown to be the best techniques for quantification.