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MM: Metall- und Materialphysik

MM 25: Poster Session

MM 25.5: Poster

Mittwoch, 29. März 2006, 15:30–17:30, P4

Elastic properties of the fine-grained materials produced by severe plastic deformation — •Przemyslaw Witczak, Zbigniew Witczak, Jolanta Borysiuk, and Ryszard Jemielniak — Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29, 01-142 Warszawa, Poland

The effect of the microstructure on elastic properties of severely deformed materials has been investigated. The hydrostatic extrusion was used to avoid microcracking in the materials being deformed. The pure copper and the dispersion-strengthen aluminium alloy were deformed at room temperature while the NiAl intermetallic compound was subjected to the hot hydrostatic extrusion. The total true strains of 4.2-6.5 were applied. Finally, the fine-grained materials were obtained with the average grain sizes in the range of 100-200 nm. The microstructure and elastic properties of the material were controlled at each stage of the deformation process. To take into account the developing texture in the material its full tensor of elasticity was measured using a resonant ultrasound spectroscopy (RUS) method. To describe the evolution of elastic properties with deformation the bulk modulus as the quantity independent of the texture and the equivalent elastic moduli of the isotropic material were calculated at each state of the process. The dependence of elastic properties on the equivalent true strain and the grain size of the material were obtained. As a final result of the refinement of the microstructure of the investigated materials to the grain size of 100-200 nm the reduction of their bulk moduli by 10-20 % was noticed. These results are discussed comparing them with the theoretical predictions.