Role of rare-earth yttrium in the hydrogen embrittlement of AISI 321 austenitic stainless steel

摘要

The hydrogen embrittlement of AISI 321 austenitic stainless steel without and with 0.045 wt rare-earth yttrium was studied with slow strain rate test, X-ray diffraction, scanning electron microscopy, electron back scattered diffraction, and transmission elec-tron microscopy. The results indicate that rare-earth microalloyed AISI 321 austenitic stainless steels show better ductility in a hydrogen environment, where the plastic loss of a specimen with 0.045 wt yttrium is 25.27 +/- 3.74, which is significantly lower than that of a specimen without yttrium (35.02 +/- 1.95). There are two important roles of rare earth yttrium in hydrogen embrittlement of AISI 321 austenitic stainless steels. The first is that rare-earth yttrium tends to interact with titanium and improves the stress concentration around Ti(C, N) by reducing its size and increasing its number. In addition, rare-earth yttrium contributes to reducing the inclination of stress and hydrogen-induced martens-itic phase transformation in metastable AISI 321 stainless steel. This work is valuable for improving resistance of austenitic stainless steel to hydrogen embrittlement.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.