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MM: Fachverband Metall- und Materialphysik
MM 50: Mechanical properties III - Evolution & deformation of microstructure
MM 50.7: Vortrag
Donnerstag, 3. April 2014, 11:45–12:00, IFW B
Influence of pressure during high pressure torsion of NiAl — •Christine Tränkner1, Robert Chulist2, Werner Skrotzki1, Benoît Beausir3, Thomas Lippmann4, Jelena Horky5, and Michael Zehetbauer5 — 1Institut für Strukturphysik, Technische Universität Dresden, Dresden, Germany — 2Instytut Metalurgii i Inzynierii Materiałowej, Polskiej Akademii Nauk, Kraków, Poland — 3Laboratoire d'Etude des Microstructures et de Mécanique des Matériaux, Université de Lorraine, Metz, France — 4Institut für Werkstoffforschung, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany — 5Fakultät für Physik, Universität Wien, Wien, Austria
NiAl is an intermetallic compound with a brittle-to-ductile-transition temperature at about 300°C and ambient pressure. As shown in [1], fracture stress and fracture strain are increased under high pressure. Therefore, deformation at low temperatures is only possible at high pressures, as for instance used in high pressure torsion (HPT). In order to study the influence of pressure on texture evolution and microstructure formation, small discs of polycrystalline NiAl were deformed by HPT at temperatures ranging from room temperature to 500°C and pressures from 2 to 8 GPa. For low temperatures higher pressures lead to less cracking and slipping. Regarding texture, pressure mainly influences the intensities of the texture components. Grain size also changes with pressure. For deformation at 500°C, the grains in the 2 GPa sample are twice as large as in the material deformed at 8 GPa. The results will be discussed with regard to dynamic recrystallization.
[1] R. Margevicius et al., Met. Mater. Trans. A 25, 1994, 1457-1470.