Hydrogen-induced fast fracture in notched 1500 and 1700 MPa class automotive martensitic advanced high-strength steel

• Published in: Corrosion science 2021-08, Vol.188, p.109550, Article 109550
• Main Authors: Venezuela, Jeffrey, Hill, Timothy, Zhou, Qingjun, Li, Huixing, Shi, Zhiming, Dong, Futao, Knibbe, Ruth, Zhang, Mingxing, Dargusch, Matthew S., Atrens, Andrej
• Format: Article
• Language: English
• Subjects: A. Advanced high-strength steel; A. Martensite; B. Linearly increasing stress test (LIST); C. Fracture velocity; C. Hydrogen embrittlement; C. Hydrogen-induced fast fracture; Crack initiation; Ductile fracture; Ductility; Fracture mechanics; Fugacity; Heat treating; High strength steels; Hydrogen; Hydrogen embrittlement; Intergranular fracture; Martensitic stainless steels; Tensile strength
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2021.109550

•Hydrogen-induced fast fractures (HIFF) initiated when the load-controlled specimen became mechanically unstable.•HIFF susceptibility was increased by increasing steel strength, increasing hydrogen fugacity, and decreasing stress rate.•The HIFF exhibited brittle features, such as quasi-cleavage, transgranular and intergranular fracture, suggesting a decohesion mechanism.•These features increased in area with increasing hydrogen embrittlement.•The HIFF velocity (61−130 m/s) was greater than the velocity of ductile fracture (46 m/s). Hydrogen embrittlement of notched martensitic advanced high-strength steels was studied. Notched specimens had (i) higher tensile strength and lower ductility, and (ii) increased hydrogen sensitivity, manifested by reductions in ductility and strength. Hydrogen-induced fast fractures (HIFF) initiated when the load-controlled specimen became mechanically unstable. The HIFF velocity (61−130 m/s) was greater than the velocity of ductile fracture (46 m/s). HIFF susceptibility increased with increasing steel strength, increasing hydrogen fugacity, and decreasing stress rate. HIFF exhibited brittle features (quasi-cleavage, transgranular and intergranular fracture) in the initiation zone, suggesting hydrogen-enhanced plasticity-mediated decohesion (HEPD). These features increased in area with increasing hydrogen embrittlement.