Dresden 2006 – wissenschaftliches Programm

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MM: Metall- und Materialphysik

MM 20: Amorphous and Liquid Materials I

MM 20.4: Vortrag

Dienstag, 28. März 2006, 15:30–15:45, IFW D

Glass forming ability and thermal behavior of Ni-based alloys — •Konrad Eymann, Uta Kühn, Helmut Hermann, Norbert Mattern, and Ludwig Schultz — IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany

The Ni-based alloys Ni-Zr-Al-Y [1], Ni-Nb-Ti-Zr-Co-Cu [2], Ni-Nb-Sn [3], and Ni-Cu-Ti-Zr-Al [4] were evaluated concerning their glass forming ability (GFA) by preparing ribbons and bulk specimens in form of cylindrical rods with diameters of 2 or 3 mm. The samples were prepared by melt spinning technique as well as by copper mold casting. The microstructure of the ribbons and rods were characterized using XRD measurements and TEM. The thermal behavior was measured by DSC. For example the glass transition temperature was used for the calculation of the parameter gamma [5] to evaluate the Ni-alloy with the best theoretical GFA. The gamma-parameter was compared to the actual microstructure of the bulk samples. The alloy with the highest GFA was found to be Ni-Cu-Ti-Zr-Al. To enhance the GFA of this alloy the composition was modified by adding further elements. The elements were chosen by computer simulations using the Bernal’s model of simple liquids generalized for multicomponent metallic systems, which finally lead to a liquid with optimized density.

[1] Yi, S. et al., Mater. Lett. 48, 258 (2001). [2] Zhang, T. et al., Mater. Trans. 43, 4, 708 (2002). [3] Choi-Yim, H. et al., Appl. Phys. Lett. 82, 7, 1030 (2003). [4] Xu, D. et al., Acta Mater. 52, 3493 (2004). [5] Lu, Z.P. et al., Acta Mater. 50, 3501-3512 (2002).