The IF Spectrum of Fe-C-N and Fe-17%Cr-C-N Alloys Measured by the Impulse Excitation Technique

The temperature dependence of the dynamic Young's modulus, E, and the damping, Q(-1), of Fe-C-N and Fe-17%Cr-C-N alloys with different C, N contents were studied in the temperature range of 25 degrees C to 600 degrees C by the impulse excitation internal friction technique at 11(Hz. Hot rolled samples were cold rolled to a thickness of 1.2mm and recrystallization annealed at 820 degrees C for 30sec then gas jet cooled (-50 degrees C/sec). Samples were subsequently tensile strained 6% and 16%. A Snoek peak was observed at 120 degrees C in the undeformed sample and a Snoek-Koster peak was observed at 400 degrees C after deformation. In the case of the Fe-Cr-C-N alloy, a high damping background due to magneto-mechanical damping was observed in the temperature range of 25 degrees C to 400 degrees C. A broaden Snoek peak in FeCr was observed at 300 degrees C. The internal friction peaks observed in this study showed the strong dependence of the amount of interstitial contents and deformation and were well correlated to previous internal friction studies measured mainly by torsion pendulum and inverted torsion pendulum.