Production by planetary ball milling and phase transition of Fe–Nd–Nb nanocrystalline alloys

Abstract

The main aim of the present work is to study the synthesis and phase transition of Fe₇₇Nd₁₀Nb₇B₄Cu₁Ag₁ magnetic nanostructured materials under high temperature conditions. Fe₇₇Nd₁₀Nb₇B₄Cu₁Ag₁ alloy powders were prepared by high energy ball milling using milling times of up to 50 h. The as milled alloys consist of an iron based nanocrystalline solid solution with an average grain size of 12·5 nm (after 50 h milling time). The evolution of grain size during the ball milling process and investigations under external temperatures up to 875°C were evaluated using synchrotron radiation X-ray diffraction and α-Fe→γ-Fe phase transition (onset transition temperature T_x1 = 825°C), and the formation of Fe₁₇Nd₂B compound (onset temperature T_x2 = 875°C) was observed. The X-ray experiments were performed at the B2 instrument beamline at DESY/HASYLAB, Hamburg, Germany.

Keywords:

• Nanostructured materials
• Mechanical alloying
• Powder diffraction

The author wishes to acknowledge Dr R. Nicula (Rostock University) for help and support with alloy synthesis and in situ XRD experiments performed at the beamline B2 from DESY-HASYLAB.