Internal Friction of Iron Cathodically Charged with Hydrogen

Abstract

The internal friction of iron cathodically charged with hydrogen was measured asa function of temperature in the range between -50°C and room temperature by the transverse vibrational mode.
Five relaxation peaks including hydrogen cold-work peak were found in this temperature region and studies were made of the characteristics of four new peaks, P₁, P₂, P₃ and P₄, which appeared at around -60°C, -45°C, -10°C and +3°C at 1KHz, respectively.
Possible mechanisms for the process responsible for these peaks are proposed as follows;
P₁ Peak: Motion of hydrogen-vacancy complex pinning down dislocations.
P₂ Peak: Reorientation of hydrogen cluster by an applied stress.
P₃ and P₄ Peak: Redistribution of hydrogen in the stress field of carbon-vacancy complex by an applied stress.