Detection of hydrogen effusion before, during, and after martensitic transformation: Example of multiphase transformation-induced plasticity steel

The effects of martensitic transformation on microstructural hydrogen distribution in a multiphase transformation-induced plasticity (TRIP) steel were investigated using silver decoration before and after cooling and cryogenic thermal desorption spectroscopy (C-TDS) during cooling. Transformation-induced hydrogen effusion occurred; however, there was a significant difference between the temperature of the peak hydrogen desorption rate and the start temperature of the martensitic transformation, in contrast to the findings of a previous study on fully austenitic steels. Furthermore, the silver-decoration experiment clarified that martensitic transformation caused a significant increase in local hydrogen flux and accordingly enhanced the heterogeneity of the hydrogen distribution, which originates from the transformation-induced hydrogen effusion observed in the C-TDS analysis. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.