Hydrogen embrittlement studies of hot-stamped boron steel with different prior austenite grain sizes

• Published in: Journal of materials science Vol. 58; no. 48; pp. 18187 - 18206
• Main Authors: Liu, Yi, Lian, Junhe, Han, Xianhong, Yang, Yi, Yuan, Haibing
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.12.2023; Springer Nature B.V
• Subjects: Accumulation; Austenite; Boron steels; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Crystallography and Scattering Methods; Dislocation density; Electron back scatter; Grain size; Heat treatment; Hot stamping; Hydrogen; Hydrogen charging; Hydrogen embrittlement; Materials Science; Metals & Corrosion; Polymer Sciences; Sensitivity; Solid Mechanics; Thermal desorption spectroscopy
• ISSN: 0022-2461; 1573-4803
• DOI: 10.1007/s10853-023-09181-0

The present study investigated the effect of the prior austenite grain (PAG) size on hydrogen embrittlement (HE) sensitivity of ultra-high strength hot-stamped steel B1500HS. To achieve different PAG sizes, varying heat treatments were implemented by tuning the austenitizing temperature and soaking time. The statistical information about grain size and dislocation density of the produced steels was measured by electron backscatter diffraction (EBSD). The electrochemical hydrogen charging method and thermal desorption spectroscopy were utilized to introduce hydrogen and measure hydrogen content, respectively. Furthermore, hydrogen microprint technique (HMT) was adopted to visualize the accumulation of hydrogen in specimens. Interestingly, it was found that the HE resistance decreased with the refinement of PAG size. This phenomenon can be attributed to two major aspects: the refined PAG size leading to a higher dislocation density which increased the HE sensitivity, and hydrogen accumulation at fine PAG boundaries, promoting local high hydrogen concentration and ultimately resulting in high HE sensitivity. Graphical abstract