相关论文: Numerical Simulations of the Invar Effect in Fe-Ni…

The Fe$_{0.64}$Ni$_{0.36}$ alloy exhibits an anomalously low thermal expansion at ambient conditions, an effect that is known as the invar effect. Other Fe$_{x}$Ni$_{1-x}$ alloys do not exhibit this effect at ambient conditions but upon…

We present a necessary condition under which a collinear ferromagnet Fe$_{1-x}A_{x}$ ($A={\rm Pt},{\rm Ni}$) with disordered face-centered-cubic structure exhibits the Invar effect. The condition involves the rate at which the fraction of…

The structural and magnetic properties of Fe$_{1-x}$Ni$_x$~($x$ = 0.32, 0.36, 0.40, 0.50) alloys have been investigated using synchrotron based x-ray diffraction (XRD) technique with x-rays of wavelength 0.63658 \AA\ down to 50 K…

We investigate the ground state properties of Invar alloys via detailed study of the electronic structure of Fe$_{1-x}$Ni$_x$ alloys ($x$ = 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.9) employing $x$-ray photoelectron spectroscopy (XPS). While all the…

Certain alloys of iron and nickel (so-called 'Invar' alloys) exhibit almost no thermal expansion over a wide range of temperature. It is clear that this is the result of an anomalous contraction upon heating which counteracts the normal…

Thermal lattice expansion of the Invar Fe65Ni35 alloy is investigated in first-principles calculations using the spin-wave method, which is generalized here for the ferromagnetic state with short range order. It is shown that magnetic…

A hybrid ab initio theoretical approach for examining thermal properties in magnetic systems of unknown entropy is presented. Commonly used theoretical approaches interrogate thermal properties from Gibbs/Helmholtz free energies, which…

This thesis is a theoretical study of thermodynamic, point-defect formation and diffusion properties in Fe-Ni alloys with a focus on the magnetochemical effects. The results are derived from density functional theory (DFT) calculations and…

Using first-principles calculations, in conjunction with Ising magnetism, we undertake a theoretical study to elucidate the origin of the experimentally observed Invar effects in disordered fcc iron-based ferromagnets. First, we show that…

Recent experiments on Pd$_{3}$Fe intermetallics [Phys. Rev. Lett. 102, 237202 (2009)] have revealed that the system behaves like a classical invar alloy under high pressure. The experimental pressure-volume relation suggests an anomalous…

The invar phenomenon (very small thermal expansion in some iron alloys or compounds) is usually explained by the thermally-induced transitions between different spin states of Fe, having different atomic volumes. We consider these processes…

An increase of the critical resolved shear stress of Invar alloys (Invar hardening) with a lowering temperature is explained. The effect is caused by a growth of the exchange interaction between dangling $d$-electron states of dislocation…

Based on state-of-the-art density-functional-theory methods we calculate the stacking-fault energy of the paramagnetic random Fe-22.5at.%Mn alloy between 300-800 K. We estimate magnetic thermal excitations by considering longitudinal…

Atomistic spin model simulations are immensely useful in determining temperature dependent magnetic prop- erties, but are known to give the incorrect dependence of the magnetization on temperature compared to exper- iment owing to their…

In this work, the evolution of nanomechanical properties was studied systematically as a function of temperature, chemical, and microstructural complexity of different Fe-based alloys. Experiments were performed at different temperatures…

We studied the structural and magnetic properties of the solid solution Fe$_{1-x}$Ni$_{x}$B through theoretical and experimental approaches. Powder X-ray diffraction, X-ray Pair Distribution Function analysis, and energy dispersive X-ray…

Research over the years has shown that the formation of the Fe$_3$Si phase in FINEMET (Fe-Si-Nb-B-Cu) alloys leads to superior soft magnetic properties. In this work, we use a CALPHAD approach to derive Fe-Si phase diagrams to identify the…

Ferromagnetic resonance has been used to study the magnetic properties and magnetization dynamics of polycrystalline Fe$_{1-x}$V$_{x}$ alloy films with $0\leq x < 0.7$. Films were produced by co-sputtering from separate Fe and V targets,…

The structure, magnetic and martensitic properties of Fe doped Ni-Mn-In magnetic shape memory alloys have been studied by differential scanning calorimetry, magnetization, resistivity, X-ray diffraction (XRD) and EXAFS. While…

We use a combination of the coherent potential approximation and dynamical mean field theory to study magnetic properties of the Fe$_{1-x}$Ni$_x$ alloy from a first principles. Calculated uniform magnetic susceptibilities have a…