Abstract
In aid of the study on heat resisting steels, the internal friction of iron and iron-chromium and iron-molybdenum alloys was investigated. The results obtained are as follows:
(1) The Q−1−T curve of iron has two peaks at about 500°C and 630°C. (2) The temperature of 500°C-peak rises and the activation energy increases with the carbon content. But the effect of carbon on the temperature for the 630°C-peak is small. (3) Chromium suppresses the 500°C-peak. The temperatures of both peaks do not change remarkably by chromium additions, while the activation energy for the 630°C-peak increases with the chromium content. (4) The temperatures for both peaks, especially the low temperature peak, rise with increasing molybdenum content. And the apparent activation energy of the combined peaks increases remarkably with the molybdenum content. (5) It is considered that the low temperature peak corresponds to the atom movement in the grain boundary layer, and that the high temperature peak to the lattice diffusion. Therefore, the measurement of internal friction is useful to understand the high temperature strength of solid solution alloys.
