STRUCTURE OF THE PSEUDOTERNARY Fe-30% Ni-10% Co (0,2 % B)
ALLOY RAPIDLY SOLIDIFIED BY MELT – SPINNING

D. Lamrous*, M.Y. Debili, T. Berchi

Département de Physique, Faculté des Sciences.Université Badji Mokhtar, Annaba,

BP 12 23.200 El-Hadjar, Annaba, Algéria

* Corresponding author. E-mail : lamrousd@hotmail.com

Received : 03 May 2002; revised version accepted : 15 August 2002

Abstract

The Fe–30.5%Ni–10%Co ternary alloy has a microcrystalline structure with a grain size of about 5 – 6µm. However, the addition of 0.2%B leads to wholly austenitic microcrystallized structure.The observations by optical and transmission electron microscopies of the pseudoternary rapidly solidified Fe–30%Ni–10%Co–(0,2 % B) alloy show dendritic structure with precipitation of secondary phase in the interdendritic space.The average size of a dendrite is of about 0.5 – 0.6 µm and the space between secondary arms of dendrites ls is of about 0.4 – 0.5 µm.We have determined by T.E.M that the secondary phase is a boride phase MxBy with BCC crystal structure and a lattice parameter a ~ 0,758nm.

Keywords : Rapid solidification; Melt-spinning; Iron alloys; Electron microscopy.

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