Berlin 2005 – wissenschaftliches Programm

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M: Metallphysik

M 19: Nanoskalige Materialien II

M 19.6: Vortrag

Samstag, 5. März 2005, 12:15–12:30, TU H111

Phase Formation During Solidification of a Ti-Based, In-Situ, Nanostructured Matrix Composite — •Thomas Woodcock¹, Germán Alcalá¹, Sonia Mato¹, Wolfgang Löser¹, Annett Gebert¹, Jürgen Eckert², and Ludwig Schultz¹ — ¹IFW Dresden, P.O. Box 270016, 01171 Dresden, Germany — ²TU Darmstadt, FB Material- und Geowissenschaften, FG Physikalische Metallkunde, Petersenstraße 23, 64287 Darmstadt, Germany

Ti-based, in-situ formed, nanostructured matrix composites such as Ti60Cu14Ni12Sn4Ta10 combine the high yield stress of nanocrystalline materials with the plasticity and toughness of conventional alloys. The remarkable mechanical properties arise from a microstructure, formed after Cu-mould casting, which consists of micron-scale dendrites of β-Ti solid solution in a nanoscale eutectic matrix. Detailed characterisation of the phases in the eutectic matrix has shown that they are β-Ti solid solution and the intermetallic NiTi which contains significant amounts of Cu in solution. Comparison with the ternary Ti-Cu-Ni system established that the eutectic in the composite forming alloy is metastable due to kinetic exclusion of the equilibrium phase at such compositions, CuTi2. The understanding of the solidifcation processes of such materials is important for alloy development and may lead to new materials suitable for a wider range of potential applications.