Development of <i>In-situ</i> Orientation Mapping and Microstructure Observation System for Ferrite/Austenite and Martensitic Transformations in Steel

Abstract

The unique in-situ SEM/EBSD observation system, which is available to carry out orientation mapping and microstructure observation at high temperature, was developed to observe ferrite/austenite and martensitic transformation of carbon steel directly. The system has the heating capacity over 1 000°C and rapid cooling ability of the cooling rate faster than 100°C/s. The SIM imaging shows very good performance to observe quick change in crystalline grain's shape, and microstructural evolution of secondary recrystallization grains was successfully observed. Furthermore, the in-situ observation system was applied to observe martensitic transformation of plain carbon steel and nickel contained carbon steel. Crystalline grain shape and its orientation before and after martensitic transformation of the steel are observed at the same sample position. And direct comparison of the microstructures between austenite and martensite is successfully realized.