https://hdl.handle.net/10259/8923 2026-04-17T04:13:58Z https://hdl.handle.net/10259/8922 Evaluating hydrogen embrittlement susceptibility of a 2205 DSS Peral, Luis Borja; Díaz Portugal, Andrés; Rodríguez Aparicio, Rubén; Alegre Calderón, Jesús Manuel; Cuesta Segura, Isidoro Iván Hydrogen embrittlement of a 2205 DSS has been evaluated by in-situ tensile tests at high-pressure hydrogen gas. Mechanical tests were conducted in smooth and notched samples, following the ASTM G142 standard. Hydrogen embrittlement susceptibility was studied at 70 and 140 bar. In the smooth samples, the loss of ductility was marked. However, the increase in hydrogen pressure from 70 to 140 bar seems to be practically negligible. On the other hand, in the notched samples, hydrogen damage was especially remarkable at 140 bar. Finally, hydrogen embrittlement susceptibility is also discussed based on the fracture micromechanims. 2024-01-01T00:00:00Z https://hdl.handle.net/10259/8921 Explicit implementation of hydrogen transport in metals Díaz Portugal, Andrés; Alegre Calderón, Jesús Manuel; Cuesta Segura, Isidoro Iván; Zhang, Zhiliang Hydrogen embrittlement prediction demands a numerical framework coupling a damage model with local hydrogen concentration. The inherent nonlinearity in hydrogen-stress-damage interactions challenges convergence in implicit schemes. To address this limitation, we propose a novel chemical potential-based explicit formulation for simulating hydrogen transport in metals. Our approach exploits a heat transfer analogy, linking mechanical and hydrogen transport via inelastic energy as a heat source. By employing chemical potential rather than lattice concentration, our method eliminates the need for user-defined boundary conditions and hydrostatic stress gradient determination. We integrate a VUMATHT subroutine for diffusion modelling and a VUMAT subroutine for material behaviour, coupling stress and strain rates as a heat source for diffusion. Validating against a classical benchmark, we compare our explicit approach with hydrogen concentration-based methods in ABAQUS Standard and Comsol Multiphysics. Stability conditions are assessed for different mesh sizes and mass scaling densities and the capabilities of our approach are showcased for 3D simulations of notched tensile specimens. Our framework offers a novel and efficient pathway for integrating hydrogen transport with user-defined material behaviour, promising advancements in hydrogen-informed damage models. 2024-07-01T00:00:00Z https://hdl.handle.net/10259/8920 Effect of electrochemical charging on the hydrogen embrittlement susceptibility of a low-alloyed tempered martensitic steel submitted to high internal pressure Peral, Luis Borja; Díaz Portugal, Andrés; Colombo, Chiara; Alegre Calderón, Jesús Manuel; Cuesta Segura, Isidoro Iván The influence of hydrogen on the mechanical behavior of a quenched and tempered 42CrMo4 steel has been evaluated by means of high internal pressure fracture tests carried out on hydrogen precharged notched cylindrical specimens. The notched cylindrical specimens were precharged for 3 h time with 1.2 mA/cm2 in two different aqueous media: 1 M H2SO4 added with 0.25 g/l As2O3 and 3.5% of NaCl solution. Hydraulic fracture tests were performed at different ramps of pressure: 7000, 220, 80, 60 and 30 MPa/h, respectively. Hydrogen damage was more marked when the acid aqueous medium (1 M H2SO4 + 0.25 g/l As2O3) was employed. In this case, a higher hydrogen concentration was introduced, leading to hydrogen decohesion micromechanisms (HEDE) near the notched region, especially when tests were performed at 60 MPa/h. Hydrogen embrittlement susceptibility is discussed in terms of the microstructural singularities and the operative fracture micromechanisms observed in each case. 2024-04-01T00:00:00Z