A NUCLEAR-REACTION STUDY OF NITROGEN DIFFUSION INTO TITANIUM AND ITS RELATION TO MICROHARDNESS

The reaction N-14(d, alpha)-C-12 was used to measure the diffusion of nitrogen into titanium, with the beam from a 5.5 MV Van de Graaff accelerator. By bombarding with 2.6 MeV deuterons and observing the spectra at a laboratory angle of 170-degrees a fairly flat region in the excitation curve of the ground state alpha particles is found. The shape of the energy spectrum is therefore indicative of the nitrogen profile, allowing a study of about 10-mu-m from the metal surface. Titanium samples were heated in a nitrogen atmosphere for periods of 1, 2, 3 and 4 h at a temperature of 800-degrees-C. The amount of nitrogen diffused was then correlated to microhardness measurements. These measurements were compared with determinations carried out on a commercial titanium nitride coated drill.