Hydrogen effects on an amorphous Fe-Si-B alloy

Hydrogen absorption in and desorption from an amorphous Fe80B11Si9 alloy, h ydrogen effects on the microstructure of this alloy, and the possible mecha nism of hydrogen embrittlement (HE) in this alloy have been studied. Ribbon s were electrochemically charged with hydrogen at room temperature. The int eraction of hydrogen with structural defects and the characteristics of hyd rogen desorption were studied by means of thermal desorption spectroscopy ( TDS). The effects of hydrogen on the microstructure and thermal stability w ere studied using X-ray diffraction (XRD), transmission electron microscopy (TEM), electrical resistivity measurements, and differential scanning calo rimetry (DSC). The phenomenon of HE was investigated using scanning electro n microscopy (SEM) and various mechanical testing techniques. The absence o f hydride-forming elements resulted in low hydrogen solubility and low deso rption temperatures. Hydrogenation at room temperature is reported for the first time to lead to either local nanocrystallization of the amorphous pha se or transformation of nanocrystalline phases such as Fesimilar to 3.5B, o riginally present in the uncharged material, to a new nanocrystalline Fe23B 6 phase. The susceptibility of this alloy to HE is explained in terms of hi gh-pressure bubble formation.