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MM: Fachverband Metall- und Materialphysik

MM 31: Mechanical properties II - Characterisation mechanics

MM 31.1: Vortrag

Dienstag, 1. April 2014, 15:45–16:00, IFW D

Problems of understanding defect-related mechanical loss spectra in aluminium — •Hans-Rainer Sinning and Jens Bernhardt — Institut für Werkstoffe, Technische Universität Braunschweig

Aluminium is one of the most thoroughly studied materials with respect to basic mechanisms of internal friction and anelastic relaxation, such as low-temperature intrinsic dislocation relaxation (Bordoni relaxation), various kinds of dislocation - point defect interactions, grain-boundary sliding, and high-temperature dislocation processes. Although these mechanisms and related phenomena are usually treated separately, they are often overlapping or even physically connected, e.g. by common rate-controlling processes like bulk or short-circuit diffusion. This makes their identification and understanding sometimes difficult, particularly in technical Al-based materials. On the other hand, such understanding is highly desirable because of pronounced effects and high sensitivity of the spectra observed. Here we will discuss some characteristic modifications recently observed mainly in the high-temperature parts of the spectra (around the well-known "grain-boundary peak"), as introduced e.g. by ceramic reinforcements (particles or BN nanotubes), or by severe plastic deformation.