Influence of doping by Mn and Co on damping of elastic oscillations and the Young's modulus of invar Fe-Ni-C alloys

The internal friction (IF) measurements within the wide range of strain amplitudes (epsilon similar to 10(-6)-10(-4)) and, based on the measurements of a resonance frequency, the calculations of Young's modulus for f.c.c. Fe-Ni, Fe-Ni-C, Fe-Ni-X and Fe-Ni-X-C (X = Mn, Co) alloys containing nearby 30% Ni are carried out. The amplitude dependences of internal friction (ADIF) are measured by means of the resonance-vibration method at the frequencies of 1.5-2 kHz. The drastic increase of ADIF and the decrease of the Young's modulus at the introduction of carbon and somewhat less change of these characteristics at the addition of substitutional elements (Mn and Co) are revealed. The analysis is carried out within the terms of motion of 90 degrees and 180 degrees magnetic-domain walls under the elastic stresses.