GRAIN-BOUNDARY INTERNAL-FRICTION PEAKS MEASURED BY THE FORCED VIBRATION METHOD

Since the early work on grain boundary relaxation by K (e) over cap in 1947. the grain boundary internal friction peaks were mostly measured by the free decay method as a function of temperature. The validity o f this procedure is based on the assumption that the grain boundary re laxation, as a rate process, should obey the Arrhenius relationship. I n this paper, the grain boundary internal friction peaks in polycrysta lline aluminum and aluminum bicrystal were measured both as a function of frequency and as a function of temperature by the forced vibration method. The results showed that the frequency spectrum is in correspo ndence with the temperature spectrum and the Arrhenius relationship ho lds for grain boundary relaxation within a wide frequency range.