Mixed Mode Fracture Toughness Testing of Hydrogen-Charged 21Cr-6Ni-9Mn Stainless Steel and 2219 Aluminum Available to Purchase

Safe design of structural components requires an understanding of mixed-mode loading effects on crack initiation and propagation. Symmetric four-point bending (S4PB) and anti-symmetric four-point bending (AS4PB) were applied to assess the coupled effect of hydrogen and mixed mode I/II loading on crack initiation and propagation in a stable, nitrogen-strengthened austenitic stainless steel (21Cr-6Ni-9Mn) and a non-hydrogenated high strength aluminum alloy (AA2219-T851). Single edge notched bend (SEN(B)) specimens were extracted from forged 21Cr-6Ni-9Mn bar and AA2219 plate. Fracture profiles depend primarily on mode-mixity. Mode I fracture toughness values in the presence of hydrogen are determined for the stainless steel following a J-integral approach and compare well with literature.