Study of magnetic behavior in ball-milled nanocrystalline Fe -50 at.% Al alloy as a function of milling time

In this study, the authors prepared a series of technologically significant Fe1 -xAlx (0.2 ≤ x ≤ 0.6) alloys by two distinct methods: (a) arc melting and (b) ball milling and compared their structural and magnetic characteristics using XRD and VSM. Regardless of the synthesis method, structural analyses show that a FeAl alloy phase forms in both situations. Although FeAl alloy is formed using both processes, the diffraction patterns are indeed very different. In samples prepared by ball milling, the peaks are substantially wider than in samples obtained by arc melting. This is mostly due to the development of nanostructured disordered FeAl alloy during ball milling of the material. Aside from this, the existence of an Aluminum peak in a sample obtained by arc melting shows an unequal distribution of Al into the Iron matrix, whereas in a sample prepared by ball milling, Al is completely dissolved into the Fe lattice. Magnetic data indicate that the arc melted process favors the nonmagnetic FeAl alloy phase, whereas the ball milled method favors the weakly magnetic FeAl alloy phase. The existence of weak magnetism in a ball-milled sample is explained by considering the system's degree of nanocrystallization and disorder.

Section: Introductionmentioning

confidence: 99%

A Comparative Study of the Structural and Magnetic Properties of Arc-Melted and Ball-Milled Fe1 – xAlx Alloys

Brajpuriya¹

2023

“…However, the widespread use of FeAl intermetallics has been limited by their inherently low ductility and toughness, especially at ambient temperatures. Higher percentages of Al in FeAl intermetallics reduce the ductility [11,12]. However, it is reported that strong enhancement of diffusivity in nanophase materials [13], attributed to grain-boundary mechanisms, should have relevant consequences on the ductility at relatively low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Evolution of Magnetic Order in Nanocrystalline Fe1xAlx Alloy

Brajpuriya¹

2022

Self Cite

Over the last few decades, ordered intermetallics based on aluminides of transition metals, particularly iron, have been studied for their potential application as high-temperature structural materials. As a result of their superior physical, chemical, and mechanical qualities, such as low density, strong corrosion and oxidation resistance, and high strength at both room and increased temperatures, FeAl intermetallics are becoming increasingly appealing for materials engineering. The magnetic characteristics of Fe1 -xAlx alloys rapidly change with changes in the structural composition and, therefore, are considered as a function of x. The ball milling operation causes the formation of a solid-state reaction assisted by severe plastic deformation owing to which the crystallite size is lowered, and an unusual and interesting magnetic behavior emerges in the resulting system. 57Fe Mössbauer spectroscopy is used to investigate the evolution of magnetic order in a highenergy ball-milled Fe-Al solid solution. The Mössbauer spectra of the samples demonstrate the existence of both magnetic and paramagnetic components with the magnetic part including three sub-spectral components. In the Mössbauer spectra of Fe-rich samples, the presence of sextets and the high field component in the hyperfine field distribution (HFD) clearly indicates the high magnetic moment, whereas for the composition x  0.6, the presence of sextets indicates the formation of Fe clusters/Fe-rich phases, while the contribution of paramagnetic phases is also clearly visible from HFD for this composition.

“…This makes FeAl intermetallics with high Al concentrations suitable for structural materials used in harsh environments. But these intermetallics have not been widely used because they are not very flexible at room temperature [10][11][12][13]. Making fine-grained materials, on the other hand, has been suggested as a possible way to improve room temperature ductility [14,15].…”

Section: Introductionmentioning

confidence: 99%

TEM and XPS Study of Ball-Milled Fe1 – xAlx Alloys

Brajpuriya¹,

Gupta²,

Vij³

et al. 2022

The ball milling technique has been extensively used to prepare different metastable states with nanocrystalline microstructures from intermetallic compounds. In the present manuscript, the authors have systematically investigated the structural and electronic properties of a series of mechanically alloyed Fe1 -xAlx (0.3 ≤ x ≤ 0.6) samples using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The ball milling process causes the formation of solid-state reactions that are aided by severe plastic deformation, resulting in reduced crystallite size and interesting microstructural and electronic changes in the resulting system. The TEM results show that the crystallite size decreases to the nanometer range (between 6-8 nm) as a function of x and the metals dissolve at the nanograin boundaries. As a result of nanometric dimensions, the reactivity increases as a result of the increased surface-to-volume ratio, which leads to the FeAl alloy phase formation. The XPS survey scan shows that the samples do not have any major contamination, and the core level spectra show a slight shift of Fe2p and Al2p peaks toward higher binding energy (BE), which proves that different Fe-and Al-rich phases of FeAl alloy have formed after 5 h of milling.