Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 15: Mechanical Properties III
MM 15.4: Vortrag
Montag, 26. März 2012, 16:30–16:45, H 0106
Mechanical spectroscopy and dislocation dynamics on Al2O3 particle reinforced Al-Mg-Si (AA6061) Alloys — •Jens Bernhardt and Hans-Rainer Sinning — Institut für Werkstoffe Technische Universität, Braunschweig, Germany)
Damping measurements using the vibrating-reed technique were carried out on an industrially used Al-Mg-Si (AA6061) alloys and also on 22 % Al2O3 particle-reinforced AA6061. Three different maxima in damping were found over a temperature range from 100 K to 800 K. Two damping peaks, located between 100 K and 400 K, are clearly related to the plastically deformed state of the material. Cold rolling of homogenized, unreinforced AA6061 gave rise to a broad damping peak with a visible substructure. In plastically deformed fcc metals, this peak is well known as Hasiguti Peak and is related to an interaction between dislocations, point defects and the crystal lattice. For the reinforced, homogenized and undeformed alloy a similar broad peak was observed after a subsequent heat treatment. In this case the microplastic deformation due to the misfit between the thermal expansion coefficient of matrix and the reinforcing particles is responsible for the emergence of the peak in damping. A further discussion of damping peak properties should reveal more detailed information about the underlying mechanisms and therefore about the influence of the reinforcing phase on dislocation dynamics.