Hydrogen trapping and desorption spectra analysis in 300M ultra high strength martensitic steel - an experimental and modeling study

In the current work, the hydrogen diffusion and trapping in 300M steel were studied using the Kelvin probe and thermal desorption technique, respectively. Lattice diffusivity and activation energy for diffusion were obtained using two step permeation measurement at different temperatures. The activation energy for lattice diffusion in the material is 32kJ/mol, and the traps in the material are weak and reversible in nature with lower desorption energies (<20kJ/mol). The data obtained were used to model the diffusion and trapping behavior of hydrogen in the material. By combining continuum mechanics with finite element modeling, and integrating detailed deconvolution of thermal desorption spectra through a multi-trap diffusion framework, a rigorous methodology for the individualized optimization of detrapping parameters associated with each trap site in a complex multi-trap system is proposed. The optimized detrapping parameters were subsequently validated against experimental thermal desorption data across a range of heating rates.