Regensburg 2007 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 10: Liquid and amorphous materials IV
MM 10.2: Vortrag
Montag, 26. März 2007, 16:30–16:45, H4
FeNbB bulk metallic glass with high boron content — •Mihai Stoica1, Khalil Hajlaoui2, Jayanta Das1, Jürgen Eckert1, and Alain Reza Yavari2 — 1IFW Dresden, Institute for Complex Materials, P.O. Box 270016, D-01171 Dresden, Germany — 2LTPCM-CNRS, I.N.P. Grenoble, 1130 Rue de la Piscine, BP 75, F-38402 University Campus, France
Fe-based alloys able to form magnetic bulk metallic glasses (BMGs) are of the type transition metal -- metalloid and often contain 5 or more elements. Usually, the metalloid content is around 20 atomic %. Very recently, the Fe66Nb4B30 alloy was found to be able to form BMG by copper mold casting technique, despite its high metalloid content. Several composition with boron contents around 30 at. % or even higher were calculated since 1993 as possible compositions of the remaining amorphous matrix after the first stage of nanocrystallization of Finemet-type Fe77Si14B9 glassy ribbons with 0.5 to 1 atomic % Cu and a few percent Nb addition. Melt-spun ribbons of all calculated compositions were found to be glassy. The composition of the ternary Fe-based BMG investigated in the present study resulted as an optimization of all possibilities. The alloy is ferromagnetic with glass transition temperature Tg = 845 K, crystallisation temperature Tx = 876 K, liquidus temperature Tliq = 1451 K and mechanical strength of 4 GPa. The coercivity of as-cast samples is very low, around 1.5 A/m. The present contribution aims at discussing the thermal stability, mechanical and magnetic properties of the Fe66Nb4B30 BMG.