Accurate determination of the parameters of internal friction associated with a grain boundary

Abstract

This paper examines the internal friction associated with grain boundaries in aluminium-rare-earth (Al-RE) alloys and develops mathematical expressions for the background and grain-boundary internal friction; suggestions are made as to how the parameters in the expressions can be determined by computer. It is shown that the expressions and computing methods developed are effective and reliable and the results obtained are also satisfactory. Processing the original experimental data on grain-boundary internal friction by the new method is of universal importance in some sense. In determining a series of parameters such as the activation energy, frequency factor, beta 0 and beta H-which are the measurements of the distribution widths of the logarithm of the frequency factor and the activation energy respectively-and the relaxation strength etc., only one original curve is required by the new method. Therefore, the number of times the measurement is repeated can be greatly reduced, saving time and effort, and full use can be made of the experimental data.