In-situ micro-cantilever bending test in environmental scanning electron microscope: Real time observation of hydrogen enhanced cracking

Abstract

A novel approach of in-situ micro-cantilever bending tests is introduced, integrating nanoindentation and environmental scanning electron microscopy (ESEM) to elucidate hydrogen embrittlement (HE) in FeAl. Bending tests were performed in vacuum (~ 5 × 10− 4 Pa) and in ESEM with water vapor (180 Pa, 450 Pa) conditions, which introduce H in-situ into the cantilevers during the test. Micro-scale In-situ SEM testing provides a full control of all the parameters involved in HE as well as avoids the proximity effect from the free surface, which is always criticized in nano-scale in-situ TEM experiments. Both hydrogen induced cracking and hydrogen reduced flow stress were observed.