Austenite morphology and resistance to hydrogen embrittlement in medium Mn transformation-induced plasticity steel

Influence of austenite morphology on the hydrogen embrittlement in medium Mn transformation-induced plasticity (TRIP) steel was investigated. With nearly the same volume fraction and mechanical stability, the lath-type austenite is found to have more beneficial effect in relieving the hydrogen susceptibility compared to the equiaxed one. Slower hydrogen uptake and diffusion are confirmed in the steel with the austenite of lath-type morphology, which is possibly led by more connections between austenite grains obstructing the migration of hydrogen. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.