Microstructure of rapidly solidified Nd-Fe-Al alloys
|Waldemar Kaszuwara 1, Bartosz Michalski 1, Elżbieta Jezierska 1, Piotr Pawlik 2, Marcin K. Leonowicz 1|
1. Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland
Hard magnetic, rapidly solidified Nd-Fe-Al alloys have been studied since 1996 y. Nevertheless, a uniform, widely accepted structural model of these alloys still does not exists. The phase constitution of these alloys consists of nanostructured crystalline phases and amorphous phases. Another difficulty of structural characterisation comes from inhomogeneity of the material in respect to the chemical composition and phase constitution. The phase constitution may change along the cross section of the material due to the gradient of quenching rate. Inhomogeneities of the chemical and phase composition are also observed in areas as small as few micrometers. All these factors make interpretation of the data of structural investigations on the nanometeric level very difficult, especially for the material state of which is fare from equilibrium.
In the current work microstructure and local chemical composition were studied for the Nd60Fe30Al10 alloy. The analyses were done on the nanometric level (HRTEM) and also completed with the studies with application of SEM and Mossbauer spectroscopy. The specimens studied were either in the form of 1 mm rod or rapidly solidified ribbon, obtained with the roll speed of 30 m/s. It has been shown that the alloy contains in its volume nanometric size crystallites, partly agglomerated and exhibiting crystallographic texture. Size of the crystallites depends on the quenching rate, which also influence the composition of the amorphous phase. The HRTEM studies revealed that the crystalline grains are frequently separated by narrow layer of intermediate phase.
Presentation: Poster at E-MRS Fall Meeting 2009, Symposium H, by Bartosz Michalski
See On-line Journal of E-MRS Fall Meeting 2009
Submitted: 2009-05-11 11:40 Revised: 2009-06-07 00:48
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