Dresden 2003 – wissenschaftliches Programm
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M: Metallphysik
M 20: Mechanische Eigenschaften I
M 20.1: Vortrag
Dienstag, 25. März 2003, 10:15–10:30, IFW B
Grain refinement and texture formation during high-strain torsion of NiAl — •Burghardt Klöden1, Roland Tamm1, Carl-Georg Oertel1, Werner Skrotzki1, Leszek Wcislak2, and Erik Rybacki3 — 1Institut für Kristallographie und Festkörperphysik, Technische Universität Dresden, 01062 Dresden, Germany — 2DESY-HASYLAB, Notkestraße 85, 22603 Hamburg, Germany — 3Geoforschungszentrum Potsdam, Telegrafenberg, 14473 Potsdam, Germany
High-temperature extruded polycrystalline NiAl, an intermetallic compound with the B2-structure, has been deformed in torsion at 1000 K in a Paterson-type rock deformation machine under 400 MPa Argon confining pressure. The maximum strain rate was about 10−4s−1, the maximum shear strain about 3. To study the texture and microstructure development in the cylindrical samples from the centre to the outer mantle, i.e. with increasing strain, high-energy synchrotron radiation as well as EBSD has been used. The texture is characterized by an approximate alignment of ⟨100⟩ and {110} or {100} parallel to the shear direction and shear plane, respectively. The microstructure is characterized by a subgrain and grain structure with the grain size decreasing with strain. Moreover, the number of grain boundaries increases. Extrapolating the obtained subgrain size stress relation to maximum stresses attainable at low temperatures yields a limiting subgrain (and grain) size in the order of 700 nm. The mechanism of grain refinement will be discussed.