[en] Hydrogen was added to samples from one lot of U5.7Nb alloy, gy gamma-phase annealing under different hydrogen overpressures and with water quenching from the annealing atmosphere. Uniaxial and biaxial tensile properties at strain rates of 0.001 per second and 2000 per second were determined for this alloy in the gamma-quenched state. The presence of hydrogen reduced ductility under all test conditions, but the fracture mode remained that of the ductile dimple type. As determined by scanning electron microscopy, dimple size decreased with increasing hydrogen content. 3 references, 14 figures, 5 tables