Hydrogen-Dislocation Interaction in Austenitic Stainless Steel Studied with Mechanical Loss Spectroscopy

摘要

Mechanical loss of pre-strained and hydrogen-charged specimens of 316L austenitic stainless steel has been measured by the free-decay method using an inverted torsion pendulum at frequencies around 1 Hz. It is found that in addition to known hydrogen Snoek-like relaxation process observed at about 240 K a new peak of mechanical loss appears around 270 K. The peak has a relaxation origin with enthalpy close to 0.78 eV and pre-exponential factor of relaxation time is found to be about 10~(-12.5) s. Effects of the pre-strain and parameters of electrochemical hydrogen charging on the hydrogen peak in deformed austenitic stainless steels are measured. The obtained results are discussed in terms of the Snoek-Koster mechanism and specifics of hydrogen atomic distribution in a multi-component substitutional alloy of austenitic stainless steel. Based on the analysis the binding energy of hydrogen to dislocation in 316L steel is evaluated to be about 0.16 eV.