Effect of deep cryogenic treatment on internal friction behaviors of cold work die steel and their experimental explanation by coupling model

Research highlights: → The solute carbon amount in matrix is reduced after DCT treating for the decreasing of Snoek peak height. → The interstitial carbon atoms segregated to nearby dislocations in the process of deep cryogenic treatment. → Interpretation of the experimental data using theoretical coupling model by internal friction. - Abstract: This paper is devoted to the internal friction behaviors in cold work die steel after deep cryogenic treatment (DCT). The experimental results include the Snoek relaxation and their dependence on carbon concentration with the soaking time in liquid nitrogen as well as the Snoek-Ke-Koester (SKK) relaxation and explaining by coupling model which is based on the considering of the cooperative migration of the foreign interstitial atoms C, N, O (FIAs) caused by two kinds of interactions, including the FIAs themselves and between the FIAs with time-dependent strain field of dislocations. The decreasing of the Snoek peak height is indicated that the solute C amount in matrix is reduced after DCT treating. Moreover, the carbon atoms segregated to nearby dislocations producing a strong Snoek-Ke-Koester relaxation.