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Talks and Poster Presentations (without Proceedings-Entry):

J. Kastner, S. Baumgartner, B. Plank, B. Harrer, C. Gusenbauer, G. Requena, G. Garces:
"Microstructure characterization of thermomechanically treated Al- and Mg-alloys by high resolution X-ray computed tomography";
Talk: EUROMAT 2013, Sevilla; 09-08-2013 - 09-13-2013.



English abstract:
X-ray computed tomography (XCT) provides a volumetric map of a specimen in three dimensions, generated from a set of radiographs. Due to measurement speed and quality, XCT systems with cone beam geometry and matrix detectors have gained general acceptance. Continuous improvements in the quality and performance of X-ray tubes and devices have led to cone beam XCT systems that can now achieve spatial resolutions down to (0.5 µm)3. XCT is widely used for microstructure characterisation of light metal alloys, since various phases can be distinguished.
We report on the evolution of the different phases in AlCu4Mg1during heat treatments close to the equilibrium eutectic temperature and in semi solid state characterized and quantified by high resolution XCT.Phase identification is performed by metallography and energy dispersive X-ray analysis. The volume fraction of interdendritc phases decreases during heat treatment homogenizing the microstructure, while existing pores become bigger. Furthermore, new shrinkage pores are formed during cooling in places of former eutectic regions.
Additionally, the morphology of Long-Period Stacking Ordered (LPSO) phases in a Mg-7%Y-2%Zn alloy is evaluated by XCT in different processing conditions: as-cast, extruded, heat treated at 540°C during 4 h, ECAPed and after friction stir welding. The mechanical behaviour of the alloy is directly related to themorphology and distribution of the LPSO phase . Moreover, the extruded alloy shows superplasticity at intermediate temperature. The cracking of coarse LPSO-phase particles and their subsequent redistribution in the magnesium matrix takes place during the course of superplastic deformation, preventing magnesium grain growth. XCT provides helpful information to follow the evolution of the shape, size and distribution of the LPSO phase as well as of the void formation during the different processing routes.

Created from the Publication Database of the Vienna University of Technology.