Nanostructured FeNiZrB powders synthesized by high-energy ball milling: structural and hyperfine characterizations.

Nanostructured (Fe0.5Ni0.5)92Zr5B3 alloy was prepared by milling a blend of pre-alloyed Fe50Ni50 precursor and high purity chemical elemental powders of Zr and B in a high-energy ball mill setup. Rietveld refinement of the X-ray diffraction pattern of the final sample (30 h of milling) revealed presence of two Fe–Ni rich phases [disordered fcc γ–(Fe,Ni) alloy with Zr and B and the atomically ordered FeNi] with grain sizes in nanometer scale. Fe and Ni atoms were locally probed using extended X-ray absorption fine structure EXAFS and 57Fe Mössbauer spectroscopy. Whilst EXAFS analysis of milled samples suggested structural properties similar to the pre-alloyed precursor, Mössbauer data have shown the Fe2B phase formation after 3 h of milling, suggesting that the final material consists of nanograins of ordered FeNi (8%) and Fe2B (6%) phases dispersed in solid solution of γ–(Fe,Ni) alloy rich in nickel (86%) with Zr and B atoms impregnated in grain boundary defects. [ABSTRACT FROM AUTHOR]