Mechanical Spectroscopy in Martensitic and Cold-Worked Carbon Steels

摘要

The internal friction (IF) spectrum of a high carbon steel is measured both at low frequency (Hz-range) and at high frequency (kHz-range). It is characterized by four relaxation peaks. The peak that appears around 500 K at 1 Hz is identified with a Snoek-Koster (S-K) relaxation, and it is the object of the present study. Similar peaks of S-K type are found at the same temperature both in cold-worked tempered martensite and in untempered martensite. The peak is attributed to the interaction of screw dislocations with carbon interstitials. From tempering and cold-work effects it is concluded that the mobility of screw dislocations is highly decreased by interstitials below the peak temperature.