Some regularities of the fracture of ordered alloys based on Ni3Fe

Some regularities of the fracture of ordered polycrystals of the alloys Ni₃Fe, Ni₃(FeMn), Ni₃FeAl), Ni₃(FeCr), Ni₃(FeCr) are studied. The alloys Ni₃Fe, Ni₃(FeMn), and Ni₃(FeAl) possess low plasticity in the ordered state at the test temperatures T < 100 °C. In the 100–200 ° C temperature range a brittleness-viscosity transition is detected which is analogous to that observed in body centered cubic (BCC) metals and alloys. The transition from the brittle into the plastic state is not accompanied by a change in the metallographic picture of slip. The distinguishing peculiarity of the strain at elevated temperatures is the significant displacement of the grains along the boundaries. The temperature band of the transition from the brittle into the plastic state of ordered alloys in the tempered state (tempering from a temperature below the temperature of the order-disorder transformation) is observed at tempering temperatures above 450 °C (tests at room temperature). The results obtained permit the assumption that a reduction in the plasticity in ordering alloys based on Ni₃Fe is caused by segregation of the impurities along the grain boundaries.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 6, pp. 35–41, June, 1971.     

Change in strain hardening and elastic properties during isothermal ordering of alloys based on Ni3Fe

A study has been made of the change in the Young's modulus, yield point, hardness, hardening coefficient, slip pattern, and duration of the linear stage in the flow curves during the isothermal ordering of the polycrystalline alloys Ni₃Fe, Ni₃(Fe + 2% Al), Ni₃(Fe + 3% Mn), and Ni₃(Fe + 2.5% Cr). A definite relationship has been observed between the changes in these properties at the various stages of ordering.     

Investigation of electrical resistivity and average magnetic moment per atom of Ni3(Fe,Ti) and Ni3(Mn,Ti) alloys

The electrical resistivity and average magnetic moment per atom of Ni₃(Fe, Ti) and Ni₃(Mn, Ti) alloys were measured. X-ray structural analysis revealed the presence of the Ni₃Ti phase in Ni₃(Fe+7% Ti) and Ni₃(Fe + 10.3% Ti), and strong interaction of Ni and Ti is deduced. The introduction of Ti into Ni₃Mn reduces the antiferromagnetic Mn-Mn interaction and thus leads to greater ordering.Deceased.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 9–12, May, 1981.     

Hall effect in the ternary ordered alloys Ni3(Mn,Fe) and Ni3(Mn,Co) 1. Disordered solution solutions

The normal and anomalous Hall constants R₀ and R_s, respectively, and the resistivity have been measured for the quasibinary alloys Ni₃Mn-Ni₃Fe and Ni₃Mn-Ni₃Co. The results imply that in ternary alloys of Ni₃Mn containing slight Fe and Co impurities the hole regions of the Fermi surface make an important contribution to R₀ and that the primary scattering mechanism for the carriers corresponding to the anomalous Hall current in the alloys with Fe at room temperature is phonon scattering. It is concluded that the Fermi surface of the Ni₃Mn-Ni₃Fe alloys is closed.Translated from Izvestiya VUZ. Fizika, No. 3, pp. 21–29, March, 1970.     

Influence of doping with titanium on the electronic structure of Ni3Fe and Ni3Mn in ordering

The specific electrical resistance , mean magnetic moment of an atom of the alloy, and the anomalous Hall (R_s) and Nernst-Ettinghausen (Q_s) constants of ordered alloys Ni₃(Fe, Ti) and Ni₃(Mn, Ti) are investigated. It is suggested that there is an additional degree of delocalization of the 3d electrons of the system Ni₃(Mn, Ti) and increase in the degree of localization of 3d electrons of the system Ni₃(Fe, Ti) with small additions of Ti, with increase in the long-range-order parameter. A model of the electronic structure of the given alloys is discussed.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 56–59, October, 1981.     

Certain features of the electronic structure of ternary alloys of Ni3Mn with iron and cobalt

Features of the electronic structure of ternary alloys of the quasibinary Ni₃Mn-Ni₃Fe and Ni₃Mn-Ni₃Co systems are discussed on the basis of an analysis of the changes in the absolute thermal emf S and in the conductivity . It is concluded that all the ternary Ni₃Mn-Ni₃Fe alloys have a closed Fermi surface in both the disordered and ordered states. It is confirmed experimentally that a deep minimum appears on the state-density curve N_d(E) during the ordering of Ni₃Mn-Ni₃Fe alloys, and the alloy composition whose Fermi surface corresponds to this minimum is given.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 8, pp. 126–133, August, 1969.     

Soft magnetic properties of NiFe compacted powder alloys

It is known that Ni–Fe based alloys (permalloys) are important soft magnetic materials, which have been widely applied in the field of electronic devices and industry. The most suitable permalloys for application exhibit low value of coercivity and magnetostriction (for about 80 at% Ni), high saturation magnetic induction (for about 50 at% Ni), higher electrical resistivity (for about 35 at% Ni). The aim of this work was to investigate the structure and magnetic properties of _Ni81Fe19${\mathrm{Ni}}_{81}{\mathrm{Fe}}_{19}$ (wt%) compacted powder material in the form of small cylinders.     

Deformation hardening and temperature dependence of mechanical properties in ternary ordered alloys based on Ni3Fe I

The variation of hardening factor and resistance to deformation with the quenching and testing temperatures for ordered alloys based on Ni₃Fe was investigated. It was shown that the yield point _0.2 and flow stresses are independent of the quenching temperature right up to about 450 ° C. At higher quenching temperatures there are increases in _0.2 and in the flow stresses corresponding to small degrees of deformation ( < 10%); the highest mechanical properties are found when the quenching temperature is near the Curie point. In quenching from a temperature above the Curie point the mechanical properties and hardening factor fall suddenly to values corresponding to the disordered state of the alloys. The temperature variation of _0.2 is similar to that mentioned above. The deformation stress at high values and the hardening factor decrease with increase in testing temperature, and below the Curie point they reach values corresponding to the disordered state. The temperature variation of mechanical properties for specimens in which the formation of long-range order is suppressed by special treatment is characterized by the absence of substantial change near the Curie point. The results obtained are discussed in relation to modern dislocation theories of hardening of alloys with long-range order.     

Investigation of electronic configurations of Ni3(Fe,Ti) and Ni3(Mn,Ti) alloys

The ordinary Hall constant R_o of quenched Ni₃(Fe, Ti) and Ni₃(Mn, Ti) alloys was measured. The number of 4s and 3d electrons per atom was calculated on the basis of a four-band model. At low Ti concentrations in Ni₃(Fe, Ti) the contribution of 3d holes to R_o is negligible, but at high concentrations it is significant. The contribution of 3d holes to R_o for Ni₃(Mn, Ti) is considerable, and for Ni₃Mn and Ni₃(Mn +9.8% Ti) it is dominant. It is concluded that the changes in band energy of the bond between Ni and Ti in the considered systems are of a different nature.Deceased.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 12–14, May, 1981.     

Hydrogenation of Zr2Ni

The intermetallic compound Zr₂Ni has been found to take up hydrogen on charging at room temperature. Zr₂(NiFe) H_4.7 and Zr₂(NiFe) H_4.5 show the same structure (CuAl₂ type) as the uncharged compound but with an expanded lattice.Analysis of room temperature spectra in zero and applied fields indicates that the⁵⁷Fe atoms occupy Ni sites in Zr₂(Ni ⁵⁷Fe). Volume expansion effects account for about one third of the increase in isomer shift ( +0.58 mms^–1) observed on hydrogenation. The distribution of hydrogen atoms around the probe³⁷Fe atoms also causes a decrease of 0.23 mms^–1 in the mean value for the quadrupole splitting compared Rith uncharged Zr₂Ni.     

Note on the magnetic properties of amorphous rare-earth nickel alloys

The magnetic properties of several amorphous rare-earth nickel alloys close to 30 at% Ni have been studied in the temperature range 4.2–300 K. The Curie temperatures range from 2 K in Pr₆₉Ni₃₁. Alloys in which the rare-earth component has an orbital moment show large intrinsic coercive forces below T_c. These coercive forces vary considerably with temperature, the temperature dependence of the alloys Dy₆₉Ni₃₁ and Tb₆₉Ni₃₁ is satisfactorily described by means of an exponential law of the form H_c(_T) = H_c(0) exp(-αT).     

Impurity effect of Me=Cr,Nb or Mn third component atoms on hyperfine interactions in ordered Ni3Fe alloy

Investigations of atomic ordering in Ni₃Fe, Ni₃(Fe, Nb), Ni₃(Fe,Cr) and Ni₃(Fe, Mn) alloys at room temperature in disordered and ordered states have been carried out by Mössbauer spectroscopy method. The experimental results confirm that in case of Ni₃Fe superstructure stabilization is achieved by Nb and Mn atoms, the Cr atoms disturb this structure.     

Phase transitions and thermal expansion in Ni<Subscript>51–<Emphasis Type="Italic">x</Emphasis></Subscript>Mn<Subscript>36 + <Emphasis Type="Italic">x</Emphasis></Subscript>Sn<Subscript>13</Subscript> alloys

Thermal expansion and structural and magnetic phase transitions in alloys of the Ni–Mn–Sn system have been investigated. The spontaneous martensitic transformation in Ni_51–xMn_{36 + x}Sn₁₃ (0 ≤ x ≤ 3) alloys is found to be accompanied by high jumps in the temperature dependences of the linear thermal expansion. The relative change in the linear sizes of these alloys at the martensitic transformation is ~1.5 × 10^–3. There are no anomalies in the magnetic-ordering temperature range in the temperature dependences of the coefficient of linear thermal expansion. The differences in the behavior of linear thermal expansion at the martensitic transformation in Ni_51–xMn_{36 + x}Sn₁₃ (0 ≤ x ≤ 3) and Ni₄₇Mn₄₀Sn₁₃(x = 4) alloys have been established.     

Thermal expansion of Ni3Al-Ni3Nb alloys

Temperature dependence of the thermal expansion coefficient () of Ni₃Al-Ni₃Nb alloys was studied. All alloys were found to have an abrupt decrease of in the 500 °–550 ° temperature range. The two-phase, 94 wt.% of Ni₃Nb alloy was shown to have the lowest thermal expansion coefficient.     

Atomic configuration of microtwins in alloys having Ll2 superstructure

In the approximation of paired interatomic potentials of the Morse type, modeling is done on the atomic configuration and energy of formation of superstructure stacking faults and superstructure twinning stacking faults in the ordered alloys Cu₃Au and Ni₃Fe, and also in the intermetallide Ni₃Al. Features are observed in the local deformation of the crystal lattice defects near equilibrium (in terms of internal energy), and the principle difference in the state of the atomic surroundings of the examined plane defects is shown. In alloys of Cu₃Au and Ni₃Fe, calculations are done for different values of the long-range order parameter. A difference is detected in the variation of the energy of formation of superstructure twinning stacking faults in alloys of Cu₃Au and Ni₃Fe with the long-range order parameter. This difference correlates with experimental observation of the properties when varying the temperature in the alloys.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 31–36, November, 1987.     

A Mössbauer study of rapidly quenchedCuFe alloys — Antiferromagnetic γ-Fe

A series ofCuFe alloys containing 5, 10 and 16 at% Fe has been prepared using standard ribbon spinning techniques. It is found that samples containing significant fractions ( 5%) of Fe in the form of r-Fe can be obtained readily on quenching from the (r + liquid) phase, applied field spectra (0–5.2 T) on antiferromagnetic r-Fe at 4. 2 K indicate that the anisotropy energy is small and that spins tilt from the minimum energy configuration (spin axes perpendicular to B_appl) for B_appl 2.5T.     

Synchrotron radiation and polarized neutron study of the enhancement of orbital magnetic moment of Fe in the epitaxial NiFe/Ru multilayer

Epitaxial Ni₈₀Fe₂₀(5 nm)/Ru(x nm)/Ni₈₀Fe₂₀(5 nm) trilayers with thickness x = 0.5-3.0 were prepared on Al₂O₃ substrate. The structure, magnetic properties and magnetic depth profiles of the epitaxial Ni₈₀Fe₂₀(1 1 1)/Ru(0 0 0 1) multilayers were studied by X-ray diffraction, X-ray magnetic circular dichroism and polarized neutron reflectivity. A strongly enhanced orbital moment of Fe in the permalloy layer was observed at the Ru thickness of the first anti-ferromagnetic coupling, which might be due to an interference between two interfaces. At this Ru thickness, the neutron reflectivity data show a 0.8 nm layer at the interface with the magnetic moment perpendicular to the surface plane, which might be due to the enhanced spin-orbital coupling at interface.     

Cation distribution and entropic disordering in mixed spinel ferrite Ga0.4Fe0.6NiCr1−yAlyO4

Mössbauer measurements (4.2T298°K) indicate the presence of entropic disordering in (Ga _0.4 ³⁺ Fe _0.6 ³⁺ Al _p ³⁺ )[Ni²⁺Cr _1–y ³⁺ Al _y-p ³⁺ Fe _p ³⁺ ]O₄ and a linear increase in p with y between 0(y=0) and 0.11(y=1). Entropic spins are located only on A-sites indicating relatively large A-sublattice frustration. Weak A-B coupling could explain this separate sublattice behaviour. Magneton number, alongwith Mössbauer p values, shows B-site canting which increases with y revealing weakness of A-B interaction. Present system can be called a frustrated ferrimagnet or entropie ferrimagnet where ferrimagnetic and frustrated (entropie) spins are coexisting.     

Synthesis and characterization of electrodeposited permalloy (Ni80Fe20)/Cu multilayered nanowires

Permalloy (Ni₈₀Fe₂₀)/Cu multilayered nanowires (NWs) were electrodeposited using a template directed method from sulfate baths via pulse potential technique. Microstructures and compositions of the nanowires were characterized using various microscopy and spectroscopy techniques. To synthesize compositionally uniform nanowires with high efficiency, new sulfate baths with a high content of Ni²⁺ were developed. The effects of deposition potential and concentration of metal ions were optimized to reduce composition inhomogeneity and incorporation of copper in the permalloy layers. Composition of the NiFe layers was found to be close to 20 at% Fe with a maximum of 5 at% Cu. TEM analysis indicated that individual nanowires exhibit distinct and coherent layering structure with rough and wavy interfaces. A synthesized single nanowire was also AC dielectrophoretically assembled across the microfabricated gold electrodes for subsequent magnetoresistance measurements.     

Growth behavior and magnetic property of electroless NiCoFeP films

The electroless NiCoFeP films were deposited on a silicon substrate in a bath containing Ni²⁺, Co²⁺, and Fe²⁺ ions with a concentration ratio of 1:1.9:1.2. These films were characterized by using transmission electron microscope, energy dispersive X-ray spectrometer, and alternating gradient magnetometer for their microstructure, crystal structure, and magnetic properties. The result showed that the film deposited at the initial stage (about 10 s) consists of only one phase with a crystal structure of FCC Ni and a composition about Ni (69 at%), Co (19 at%), Fe (4 at%), and P (7 at%); The film deposited at the latter stage (about 30 s) consists of two phase, one is similar to that of initial stage and the other has crystal structure of HCP Co with a composition about Ni (35 at%), Co (44 at%), Fe (19 at%), and P (2 at%). The saturation magnetization and coercivity of electroless NiCoFeP films vary from 525 to 1546 emu/cm³ [0.68–2.01 T] and from 51.44 to 88.5 Oe [4.09–7.04 kA/m], respectively.