Role of lattice strain and texture in hydrogen embrittlement of 18Ni (300) maraging steel

Abstract Hydrogen embrittlement causes engineering components to fail unexpectedly. Maraging 300 steel was hydrogen charged and subjected to slow strain rate tensile test until fracture. Electron backscatter diffraction analysis of fractured specimen revealed that cracks initially propagated intergranulary along prior-austenite grain boundaries. When cracks faced martensitic { 111 } α planes parallel to normal direction (ND) they were deflected and continued to propagate transgranulary through { 001 } α / / ND planes. Finally, cracks were arrested by { 111 } α / / ND planes. Crystallographic planes on which cracks propagate/are arrested, correlate well with planes that exhibit highest/lowest magnitude of lattice strain determined during tensile loading using in situ synchrotron X-ray diffraction.