INTERNAL FRICTION PEAKS ASSOCIATED WITH THE STRESS-INDUCED DIFFUSION OF CARBON IN FACECENTERED CUBIC ALLOY-STEELS AND METALS

Abstract

Internal friction peaks asscciated with the presence of carbon in several types of f.c.c. alloy-steel (18/8 type stainless steel and high manganese steel) have been observed from measurements with a torsion pendulum. The temperature for maximum internal friction lies between 200-300℃with a frequency of vibration of about I cycle per second. The height uf the peak rises and the position of the peak shifts to a lower temperature with an increase of the carbon content. When the amount of carbon in solid solution is reduced by tempering the specimen at an elevated temperature, the height of the peak lowers and the peak shifts to a higher temperature. A comparison of the activation energy and the diffusion ccefficients determined by internal friction methods with those measured in conventional macro-diffusion experiments reveals that the observed internal friction peak is associated with the stress-indused diffusion of carbon in these face-centered cubic steels.Internal friction peaks associated with the stress-induced diffusion of carbon in a Ni-Al alloy and in pure nickel have also been observed. These experiments show that the appearance of an internal friction peak associated with the diffusion of carbon in f.c.c. metals may be a general phenomenon.