Pre-bainitic Transformation in Fe-Ni Alloy

The behaviour of the pre bainitic transformation in Fe Ni alloy was investigated by using SAM, X ray diffraction and TEM. The results show that there is segregation of Ni atoms in austenite and that bainite forms in depleted regions of Ni atoms.

Electroplating process of amorphous Fe-Ni-Cr alloy

A novel process of electroplating amorphous Fe Cr Ni alloy in chloride aqueous solution with Fe(Ⅱ), Ni(Ⅱ) and Cr(Ⅲ) was reported. Couple plasma atomic emission spectrometry (ICP AES), X ray diffractometry(XRD), scanning electronic microscopy(SEM), microhardness test and rapid heating cooling method were adopted to detect the properties of the amorphous Fe Ni Cr deposit, such as composition, crystalline structure, micrograph, hardness, and adherence between deposit and substrate. The effects of the operating parameters on the electrodeposit of the amorphous Fe Ni Cr alloy were discussed in detail. The results show that a 8.7?μm thick mirror like amorphous Fe Ni Cr alloy deposit, with Vicker’s hardness of 530 and composition of 45%～55% Fe, 33%～37% Ni, 9%～23% Cr was obtained by electroplating for 20?min at room temperature(10～30?℃), cathode current 10～16?A/dm 2, pH=1.0～3.0. The XRD patterns show that there only appears a broad hump around 2 θ of 41?°～47?°for the amorphous Fe Ni Cr alloy deposit, while the SEM micrographs show that the deposit contains only a few fine cracks but no pinholes.

Magnetization-Enhanced Dislocation Motion and Decreased Yield Strength of 60Fe40Ni Alloy

Using a special constant deflection device, the changes in dislocation configuration ahead of a loaded crack tip for 60Fe40Ni alloy. before and after magnetization in a magnetic field, have been studied in TEM. The results showed that the magnetization for 60Fe40Ni alloy could enhance dislocation emission, multiplication and motion. Also, the mechanical properties of 60Fe40Ni alloy, in air and in the magnetic field respectively have been investigated using the slow strain rate tension. And the results indicated that magnetization could make the yield strength corresponding to decrease by 26 percent, but did not influence the ultimate tensile strength and the fracture strain, which showed that magnetization could enhance plastic deformation.

Theoretical and experimental investigation of chemical mechanical polishing of W–Ni–Fe alloy

Fine finishing of tungsten alloy is required to improve the surface quality of molds and precision instruments. Nevertheless, it is difficult to obtain high-quality surfaces as a result of grain boundary steps attributed to differences in properties of two-phase microstructures. This paper presents a theoretical and experimental investigation on chemical mechanical polishing of W–Ni–Fe alloy. The mechanism of the boundary step generation is illustrated and a model of grain boundary step formation is proposed. The mechanism reveals the effects of mechanical and chemical actions in both surface roughness and material removal. The model was verified by the experiments and the results show that appropriately balancing the mechanical and chemical effects restrains the generation of boundary steps and leads to a fine surface quality with a high removal rate by citric acid-based slurry.

Electrochemical Isolation and Determination of GCP Phase in a Fe-Cr-Ni Alloy

Geometrical Close Packed (GCP) phase in Fe Cr Ni alloy was quantitatively isolated and precisely determined when electrolyzed in 10 % H 3PO 4 electrolyte at a low current density of 5 mA/cm 2 and 22 ℃±1 ℃. The transpassive dissolution potential of the alloy matrix under above conditions is about 1 140 mV (SCE), at which GCP phase is in passive state and can be isolated from the alloy.[WT5”HZ〗

Cavitation Erosion Behavior of as-Welded Cu12Mn8Al3Fe2Ni Alloy

Cavitation erosion behavior of as-welded Cu12Mn8Al3Fe2Ni alloy in 3.5% NaCl aqueous solution was studied bymagnetostrictive vibratory device for cavitation erosion. The results show that the cavitation erosion resistance ofthe as-welded Cu12Mn8Al3Fe2Ni alloy is much more superior to that of the as-cast one. The cumulative mass lossand the mass loss rate of the as-welded Cu12Mn8Al3Fe2Ni alloy are almost 1/4 that of the as-cast one. SEM analysisof eroded specimens reveals that the as-cast Cu12Mn8Al3Fe2Ni alloy is attacked more severely than the as-weldedone. Microcracks causing cavitation damage initiate at the phase boundaries.

Modification of short-range repulsive interactions in ReaxFF reactive force field for Fe–Ni–Al alloy

The short-range repulsive interactions of any force field must be modified to be applicable for high energy atomic collisions because of extremely far from equilibrium state when used in molecular dynamics(MD)simulations.In this work,the short-range repulsive interaction of a reactive force field(ReaxFF),describing Fe-Ni-Al alloy system,is well modified by adding a tabulated function form based on Ziegler-Biersack-Littmark(ZBL)potential.The modified interaction covers three ranges,including short range,smooth range,and primordial range.The short range is totally predominated by ZBL potential.The primordial range means the interactions in this range is the as-is ReaxFF with no changes.The smooth range links the short-range ZBL and primordial-range ReaxFF potentials with a taper function.Both energies and forces are guaranteed to be continuous,and qualified to the consistent requirement in LAMMPS.This modified force field is applicable for simulations of energetic particle bombardments and reproducing point defects'booming and recombination effectively.

THE MAGNETORESISTANT BEHAVIOR OF Ni_(85)Fe_(15) ALLOY FILM IMPLANTED BYCo^+

Implanting 1 ×1016 to1 ×1017 Co+/cm2 into Ni85 Fe15 alloy film anditschangesof mag netoresistantcharacters were researched . The results show that Co+ is very spectacular on modifying Ni85 Fe15 alloyfilm’s magnetoresistancecharacters. Atlower dose,theanisotrop ic magnetoresistivity ratio( AMR) and thesaturated magnetic field didn’tchange almost. ATmedium dose, the saturated magnetic field does not have great change either, butits AMRisraised from 1 % upto 3% . Thisiscomparabletothebest AMRvalueof permalloy based magnetoresistant material prepared by other methods. But the ion implantation tech niqueisrathersimpler. Whentheimplanting doseishigher,its AMRisalsoenhanced notice ably. However,theincreaseof saturated field saysthe material’sstructurecharacters have changed radically.

Microstructure,tribological behavior and magnetic properties of Fe−Ni−TiO_(2) composite coatings synthesized via pulse frequency variation

The Fe−Ni−TiO_(2) nanocomposite coatings were electrodeposited by pulse frequency variation.The results showed that the nanocomposite with a very dense coating surface and a nanocrystalline structure was produced at higher frequencies.By increasing the pulse frequency from 10 to 500 Hz,the iron and TiO_(2) nanoparticles contents were increased in expense of nickel content.XRD patterns showed that by increasing the frequency to 500 Hz,an enhancement of BCC phase was observed and the grain size of deposits was reduced to 35 nm.The microhardness and the surface roughness were increased to 647 HV and 125 nm at 500 Hz due to the grain size reduction and higher incorporation of TiO_(2) nanoparticles into the Fe−Ni matrix(5.13 wt.%).Moreover,the friction coefficient and wear rate values were decreased by increasing the pulse frequency;while the saturation magnetization and coercivity values of the composite deposits were increased.

Influence of boron-doping on the H2-induced environmental embrittlement of Ni3Fe intermetallics

In this paper the tensile properties of both ordered and disordered Ni-24Fe and Ni-24Fe-0.03%B （wt%） alloys in gaseous hydrogen was investigated. The result shows that the ductility of the disordered Ni3Fe is significantly larger than that of ordered material in gaseous hydrogen. However, the ductility of ordered Ni3Fe doped with 0.03%B is nearly the same as that of disordered one indicating the obvious suppressing effect of boron on the H2-induced embrittlement. Based on the segregation behavior of boron in Ni3A1, it is proposed that the suppressing effect of boron in Ni3Fe on the H2-induced embrittlement is attributed to the segregation of boron on grain boundaries, thereby reducing the hydrogen diffusivity along the grain boundaries.

Studies on Structure and Electrocatalytic Hydrogen Evolution of Nanocrystalline Ni-Mo-Fe Alloy Electrodeposit Electrodes

Nanocrystalline Ni Mo Fe alloy deposits were obtained by electrodeposition. The structures of the alloy deposits were analyzed by X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). The XRD results of nanocrystalline Ni Mo Fe alloy deposit show that many diffraction lines disappear, and that there is only one diffraction peak at 44.0°. The XPS results of nanocrystalline Ni Mo Fe alloy deposits indicate that the nickel, molybdenum and iron of the deposits exist in metallic state, and that the binding energy of the alloyed elements increases to some extent. The nanocrystalline Ni Mo Fe alloy deposit electrode may offer better electrocatalytic activity than the polycrystalline nickel electrode and the nanocrystalline Ni Mo alloy electrode. The electrochemical impedance spectra from the nanocrystalline Ni Mo Fe alloy electrode indicate that hydrogen evolution in 30% ( m/m ) KOH at lower overpotential is in accordance with the Volmer Tafel mechanism, but with the Volmer Heyrovsky mechanism at higher overpotential.

Synthesis of growth-type polycrystalline diamond compact (PDC) using the solvent Fe_(55)Ni_(29)Co_(16) alloy under HPHT

A growth-type polycrystalline diamond compact （PDC） was synthesized under high temperature and high pressure （HPHT）. The infiltration technique was used with an Fe55Ni29Co16 （KOV） alloy as the sintering solvent. The morphology and weight ra- tio of the PDC were investigated through scanning electron microscopy （SEM） and electron dispersion spectroscopy （EDS）. Note that the KOV alloy evenly infiltrated throughout the polycrystalline diamond （PCD） layer and WC-Co substrate in a short sintering time due to its low viscosity and high soakage capability. A transition layer confirmed the presence of the M^C phase near the interface of the PDC, which can make the diamond layer and WC-Co substrate combine as a complex material. X-ray diffraction （XRD） performed on the PCD layer confirmed the presence of cubic diamond, WC, cubic CoCx, the high tempera- ture cubic phase of c^-Co, the alloy phase of FeNix, and no graphite phase. Besides, a surface residual stress of the PCD layer, measured with reasonable accuracy using micro-Raman spectroscopy, is found to be a homogeneous compressive stress with an average value of 0.16 GPa, much lower than that of the powders-mixing method.

Laser Powder Bed Fusion Processing of Soft Magnetic Fe–Ni–Si Alloys: Effect of Hot Isostatic Pressing Treatment

Laser powder bed fusion(L-PBF)-processed high-silicon steel has great advantages in freely designed electric engines,and various studies have been conducted in this field.However,the analysis of both the mechanical and magnetic properties,focusing on the multiscale microstructure under as-fabricated and heat-treated conditions,which is indispensable for industrial applications,has not been performed.In this study,an Fe–Ni–Si sample was fabricated using the L-PBF process.Subsequently,the following hot isotropic pressing(HIPing)process was employed as a post heat treatment step for the Fe–Ni–Si alloys.The effects of HIPing on the microstructure were investigated,focusing on the metastable stable phase transformation in the Fe–Ni–Si system.X-ray diffraction results showed single-phase fccγ(Fe,Ni)in the L-PBF-processed samples before and after HIPing.Moreover,the acicular Ni/Si-rich structure(formed in the as-fabricated L-PBF sample because of its high cooling rates)transformed to the equilibrium austenite,Ni3Si,and FeNi3 phases during HIPing.After HIP,the compressive modulus and strength increased from 11 GPa and 650 MPa to approximately 18 GPa and 900 MPa,respectively.The magnetic properties were evaluated via a hysteresis loop,and the coercivity increased from 1.8 kA/m and to 2.9 kA/m after the HIPing process.