Impurity segregation at alloy grain boundaries (GB) depends on many parameters such as GB character and prior thermomechanical history. In this paper we describe an experimental set-up designed to record the individual behaviour of GB during recrystallization of a Nickel-Sulphur alloy. The aim is to correlate segregation level with mobility and disorientation of GB. Therefore a method allowing direct observation of the GB motion as well as disorientation mapping is needed.
Studying grain growth and recrystallization of this particular alloy by Scanning Electron Microscopy is possible thanks to real time in-situ imaging. This requires a sensitive crystal orientation contrast and the ability to image hot evolving samples. To heat the samples, a special device designed for the SEM analysis chamber is used. This device is used at 455°C but is able to reach higher temperatures. In order to get the orientation contrast images, as well as to protect the Secondary Electron (SE) detector from heat and light, a channel plate converter has been designed. This experimental set-up, combined with the heating system, allow the observation of the sample during recrystallization and recording small videos providing information such as grain boundary displacement rate. Then, associated with an EBSD analysis we can get the disorientation map of the area of interest and eventually an electrochemical technique is performed to create preferential dissolution at GB. Geometry of the grooves resulting from an electrochemical etching gives an evaluation of the segregation level in GB.