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M: Metallphysik

M 22: Intermetallische Phasen

M 22.5: Vortrag

Mittwoch, 10. März 2004, 17:30–17:45, H6

MODEL ALLOY BASED ON HIGH NI CONTAINING MARAGING STEEL INVESTIGATED BY 3 DIMENSIONAL ATOM PROBE — •Stefan Höring¹, N. Wanderka¹, J. Banhart¹, H. Clemens², and H. Leitner² — ¹Hahn-Meitner-Institut Berlin, Glienicker Str. 100, 14109 Berlin — ²Institut für Metallkunde und Werkstoffprüfung, Montanuniversität Leoben, Franz-Josef-Strasse 18, A - 8700 Leoben

The high Ni containing maraging steels are widely used for aerospace as well for tools and dies because of their good mechanical properties. The high strength of these steels is achieved by dispersion of precipitates in nanometer scale. A model alloy based on the maraging steel with the composition 75.08 Fe - 13.09 Cr - 8.38 Ni - 1.08 Si - 0.96 Ti - 0.69 Al  - 0.57 Mo - 0.11 Mn - 0.05 C (in at. %) was solution heat treated at 1273 K for 1 h and subsequently aged at 748 K for 12 h and 100 h. The microstructure of the annealed specimens were studied by high resolution methods such as three dimensional atom probe (3DAP) and high resolution transmission electron microscopy (HRTEM). After 12 h annealing time small precipitates of spherical morphology and of about 2 nm in diameter were formed. They are enriched in Ni, Al, Ti and Si. After 100 h two additional phases were produced. One of them is enriched in Al, Ti and Ni and the other one is mainly enriched in Cr.