V. V. Vavilova

Nanocrystalline Fe-P-Si alloys

Annealing Fe-P-Si amorphous alloys was found to produce nanocrystalline particles and raise the microhardness of the alloys by a factor of 2 to 3. The most significant strengthening was observed in the alloys containing the smallest amounts of Si and P and the largest amount of the α-Fe-based phase. As shown by x-ray diffraction and electron microscopy, the alloy consisting entirely of nanocrystalline phases with a particle size of about 25 nm crystallizes in three steps.

Effect of 0.1 M Na 2 SO 4 solution on the structure and properties of amorphous and nanocrystalline Fe-P-Mn alloys

We have studied the electrochemical behavior of amorphous and nanocrystalline Fe-P-Mn alloys with different Mn contents in 0.1 M Na2SO4 as a model contamination. The results demonstrate that the alloys rapidly dissolve during anodic polarization, like an Fe-Si-B-Nb-Cu (Finemet) electrochemical alloy. The process involves the dissolution of both Fe and a metastable Fe2P-based phase.

Mössbauer Study of Nanoscale Crystallization in Amorphous Fe–P–Si Alloys during Annealing

The crystallization behavior of amorphous Fe–P–Si alloys is studied by Mössbauer spectroscopy and physicochemical analysis. The resulting materials are found to contain nanocrystalline particles of complex composition, characterized by a doublet and several sextets in the Mössbauer spectrum. In the alloys containing 6 or 10 at. % Si, crystallization leads to the precipitation of pure Fe, which increases Si mobility and, accordingly, the rate of particle growth.

Physicochemical Properties of Amorphous and Crystalline Fe–P–Mn and Fe–P–Mn–V Alloys

Annealing Fe–P–Mn and Fe–P–Mn–V soft-magnetic amorphous alloys prepared from ferrophosphorus waste leads to the formation of fine-particle crystalline phases. The associated structural hardening is more pronounced in alloys with stronger interatomic interactions. The dissolution of Mn and V inhibits the growth of Fe3P particles, which become smaller than the α-Fe particles.

Fe-P-M (M = Si, Mn, V) alloys: Viscosity in the liquid state and tendency to amorphization

The viscosity of Fe-P-M (M = Si, Mn, V) melts was measured. The effects of the alloying elements on melt viscosity and the tendency of the alloys to amorphize were shown to increase in the order Si → Mn → V. By combining alloying elements, amorphous alloys were prepared which crystallize in three and four steps, yielding multiphase materials.

Effect of pulsed photon irradiation on the formation of a nanocrystalline structure in Fe-Pb-Nb amorphous alloys

X-ray diffraction, transmission electron microscopy, and microhardness and internal friction measurements are used to study the formation of a nanocrystalline structure in Fe-Pb-Nb amorphous alloys subjected to pulsed photon irradiation. The threshold light energies that are incident on a sample and cause nanocrystallization and hardening of amorphous alloys are found, and a model of crystal phase nucleation in amorphous alloys is developed.

Nanostructure forming in soft magnetic Fe-P-Si-Mn-V and Fe-P-Si-Mn-V-C alloys upon annealing

The crystallization and formation of clusters and nanocrystals in amorphous Fe-P-Si-Mn-V and Fe-P-Si-Mn-V-C alloys during annealing is studied by Mössbauer spectroscopy and physicochemical analysis. The results permit the choice of optimal compositions with soft magnetic properties.

Formation of a nanocrystalline structure in an iron-base amorphous alloy under the influence of a pulsed magnetic field

Processing the amorphous Fe77P13Si5Mn2.4V0.2C2.4 alloy with one or four 1-ms magnetic pulses of energyE = 1, 5, or 7 kJ was found to reduce the size of coherently scattering domains and notably raise the strength of the alloy, especially atE = 5 kJ. Mössbauer spectroscopy and x-ray diffraction data demonstrate that annealing at 773 K for 10 min and pulsed magnetic processing withE = 5 kJ give rise to the formation of a large number of nanocrystalline phases containing Fe atoms in various states.

Nanocrystallization and change in the properties of an Fe80.2P17.1Mo2.7 amorphous alloy during heat or photon treatment

The changes in the phase composition and the mechanical and magnetic properties resulting from the nanocrystallization of an Fe80.2P17.1Mo2.7 amorphous alloy activated by heat or fast photon (xenon lamp radiation) treatment are compared using X-ray diffraction, Mössbauer spectroscopy, transmission electron microscopy, and hardness measurements. The initial stages of crystallization of the amorphous alloy have been detected.

Electrochemical behavior of a nanostructured Fe-P-V alloy in 0.1 M Na2SO4 solution

This paper examines the electrochemical behavior and structural changes of an Fe-P-V alloy in a 0.1 M Na2SO4 solution modeling a SO2-contaminated humid atmosphere.