Internal friction in neutron-irradiated iron alloys

The interstitial solute carbon and nitrogen atoms in neutron irradiated Fe-Ni-N and Fe-Cu-C alloys were investigated by internal friction measurements. The composition of the alloys is given as are the heat treatments prior to neutron irradiation, the irradiation temperatures and neutron doses. Internal friction was determined from the natural decay of the transversal resonance vibration of plate specimens 1x10x100 mm in size. The measurements of internal friction were performed during heating at a rate of about 1 degC.min-1 and the same specimen was annealed from a low to a higher temperature successively for 30 min. The third additional elements in α-iron (N,C) raise the resolution temperatures of the interstitial solute atoms. The order of the resolution of nitrogen atoms in the Fe-Ni-N alloy is about 2.6 and the activation energy of the resolution is 2.9 eV. (B.S.)