The mechanism investigation of deep cryogenic treatment on high alloy martensitic steel by low frequency internal friction

Effects of deep cryogenic treatment (DCT) on the internal friction (IF) in high-carbon alloy steel are investigated. The temperature dependent internal friction (TDIF) of the quenched and DCT treated samples were measured in an inversed torsion pendulum with high vacuum by using free decay method. The TDIF of quenched sample is decomposed into four peaks: P1 at 342 K, P2 at 443 K, P3 at 492 K and P4 at 580 K. Peak P1 is attributed to the relaxation associated with the reorientation of interstitial solute atoms in metals under the application of oscillatory stress. Peak P2 is related to the carbides precipitation. Peak P3 is considered as the Snoek-Kê-Köster (SKK) peak, which is caused by both dislocations interaction and interstitial atoms decorating these dislocations. Peak P4 is attributed to retained austenite transformation basing on the peak disappearing while the samples carried out DCT treating.