Hydrogen diffusivity in different microstructural components in martensite matrix with retained austenite

We elucidate the hydrogen diffusivity in martensite matrix with retained austenite (RA). Two aspects are focused: effect of microstructure on hydrogen diffusion behavior; hydrogen diffusivity calculation for different microstructural components. Quenched martensite (QM) had the highest effective hydrogen diffusion coefficient because of high dislocation density. Effective hydrogen diffusion coefficient decreased with the increase of intercritical annealing temperature because of decrease in dislocation density and increase of RA. According to the principle of Maxwell-Garnett equation, the hydrogen diffusion coefficient for grain boundary (GB) was 7.99 x 10(-8) m(2)/s and hydrogen diffusion coefficient of tempered martensite (TM) was 7.84 x 10(-11) m(2)/s. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study focused on elucidating hydrogen diffusion behavior in martensite matrix with retained austenite (RA), with a specific emphasis on the effect of microstructure on hydrogen diffusion behavior and hydrogen diffusivity calculation for different microstructural components. The highest effective hydrogen diffusion coefficient was observed in quenched martensite (QM) due to its high dislocation density. However, the effective hydrogen diffusion coefficient decreased as intercritical annealing temperature increased, attributed to the decrease in dislocation density and increase of RA. Furthermore, according to the Maxwell-Garnett equation, the hydrogen diffusion coefficient for grain boundary (GB) was 7.99 x 10(-8) m(2)/s and for tempered martensite (TM) was 7.84 x 10(-11) m(2)/s.