ISSN:
1013-9826
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Internal friction in ultra-fine grained Mg with 3vol% of Graphite was measured by forcedvibration method at low frequencies of 0.1, 0.5, 1.0, and 2.0 Hz over a temperature range from roomtemperature to 753 K with continuous heating. The specimens were prepared by milling procedurein an inert atmosphere and subsequent compacted and hot extruded. Two developed peaks in theinternal friction spectrum were obtained at temperatures ≈ 350 K and ≈ 550 K. While the position ofthe first peak is frequency dependent, the second peak position is stable, independent of measuringfrequency. The activation energy of the low temperature peak was estimated. In the light of internalfriction measurements, the high temperature internal friction peak is attributed to the generation andmotion of dislocations produced by the difference in the coefficient of thermal expansion betweenthe Mg matrix and Gr phase at the matrix–particle interfaces
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.319.189.pdf
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