THE EFFECT OF ABSORBED HYDROGEN ON THE AMORPHIZATION OF CUTI ALLOYS

Neutron and x-ray diffraction measurements have been made on a series of amorphous CuTi alloys produced by mechanical alloying (MA). Parent titanium powder was used that was free from hydrogen. The copper-rich alloys were found to be fully amorphous after 16 hours of mA, but the reaction was incomplete in the titanium-rich alloys after the same period and they consisted of intermetallic phases, This is in contrast with the results for a series of samples examined by us previously, which had small contaminations of hydrogen, but which all transfor-med to an amorphous state after the same period of mA. This suggests that the presence of hydrogen stimulates the amorphization reaction and that in its absence the reaction is inhibited in the titanium-rich samples. It is also found that the degree of chemical short-range order present in the fully transformed amorphous samples is also influenced by the hydrogen contamination in the parent titanium.