The PWA 1483 single crystal super alloy, a material of interest for applications in advanced gas turbines of electrical power plants, has been investigated by internal friction and dynamic modulus measurements in the temperature range 25-800 °C. The tests have been carried out on bar-shaped samples (50 x 6 x 0.7 mm3 ) vibrating in flexural mode with resonance frequency of ∼ 350 Hz. To assess the structural stability, each sample has been subjected to several successive measurement cycles. During heating all the samples exhibit a maxima of internal friction at ∼ 350 °C, which is accompanied by an abrupt increase of dynamic modulus. The phenomenon is observed at slightly higher temperatures for higher heating rates. At the end of each cycle (when the sample has been cooled down to room temperature) the dynamic modulus is a little higher than the original value. Experimental results can be explained by assuming the presence of unstable dislocation structures which evolve after heating. Anelasticity phenomena observed by us have been ascribed to change of dislocation density and mean distance between pinning points of dislocation segments.
P., D., T., F., B., G., Montanari, R., O., T. (2007). Elastic and anelastic behaviour of PWA 1483 single crystal super alloy. ??????? it.cilea.surplus.oa.citation.tipologie.CitationProceedings.prensentedAt ??????? Intern. Conf. Applied Mechanics 2007, Ostrava.
Elastic and anelastic behaviour of PWA 1483 single crystal super alloy
MONTANARI, ROBERTO;
2007-01-01
Abstract
The PWA 1483 single crystal super alloy, a material of interest for applications in advanced gas turbines of electrical power plants, has been investigated by internal friction and dynamic modulus measurements in the temperature range 25-800 °C. The tests have been carried out on bar-shaped samples (50 x 6 x 0.7 mm3 ) vibrating in flexural mode with resonance frequency of ∼ 350 Hz. To assess the structural stability, each sample has been subjected to several successive measurement cycles. During heating all the samples exhibit a maxima of internal friction at ∼ 350 °C, which is accompanied by an abrupt increase of dynamic modulus. The phenomenon is observed at slightly higher temperatures for higher heating rates. At the end of each cycle (when the sample has been cooled down to room temperature) the dynamic modulus is a little higher than the original value. Experimental results can be explained by assuming the presence of unstable dislocation structures which evolve after heating. Anelasticity phenomena observed by us have been ascribed to change of dislocation density and mean distance between pinning points of dislocation segments.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
