Invar Alloys

Shiga, M.

doi:10.1002/9783527603978.mst0040

Cited by 7 publications

(10 citation statements)

References 163 publications

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“…This is a large increase in volume in going from the ferromagnetic to the paramagnetic state, a large increase that contrasts with the small decrease of -0.07 % observed [11] in Mn 1.1 Fe 0.9 P 0.85 Ge 0.15 . Here it should be noted that a small decrease in volume observed when going from the ferromagnetic state to the paramagnetic state, or the corresponding increase in going from the paramagnetic state to the ferromagnetic state, is the normal behavior for iron based compounds due to the so-called invar effect [14]. In the course of this work, a preliminary report [15] of the temperature dependence of the unitcell parameters of Mn 1.1 Fe 0.9 P 0.8 Ge 0.2 has become available.…”

Section: X-ray Diffraction Resultsmentioning

confidence: 99%

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn_1.1Fe_0.9P_1−xGe_xcompounds

Sougrati

Hermann

Grandjean

et al. 2008

J. Phys.: Condens. Matter

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The structural, magnetic and Mössbauer spectral properties of the magnetocaloric Mn 1.1 Fe 0.9 P 1-x Ge x compounds, with 0.19 < x < 0.26, have been measured between 4.2 and 295 K. The 295 K unit-cell volume increases from x = 0.19 to x = 0.22 and is substantially smaller in the ferromagnetic Mn 1.1 Fe 0.9 P 0.74 Ge 0.26 . The temperature dependence of the magnetization reveals ferromagnetic to paramagnetic transition with a Curie temperature between ca. 250 and 330 K and hysteresis width of 10 to 4 K, for 0.19 < x < 0.25. The composition Mn 1.1 Fe 0.9 P 0.78 Ge 0.22 shows the largest isothermal entropy change of ca. 10 J/(kgKT) at 290 K. The Mössbauer spectra have been analysed with a binomial distribution of hyperfine fields correlated with a change in isomer shift and quadrupole shift, a distribution that results from the distribution of phosphorus and germanium among the nearneighbours of the iron. The coexistence of paramagnetic and magnetically ordered phases in ranges of temperature of up to 50 K around the Curie temperature is observed in the Mössbauer spectra and is associated with the first-order character of the ferromagnetic to paramagnetic transition. The temperature dependence of the weighted average hyperfine field is well fit within the magnetostrictive model of Bean and Rodbell. Good fits of the Mössbauer spectra could only be achieved by introducing a difference between the isomer shifts in the paramagnetic and ferromagnetic phases, a difference that is related to the magnetostriction and electronic structure change.

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Section: X-ray Diffraction Resultsmentioning

confidence: 99%

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn_1.1Fe_0.9P_1−xGe_xcompounds

Sougrati

Hermann

Grandjean

et al. 2008

J. Phys.: Condens. Matter

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“…The data was fitted into the parabolic relation: o ¼ kCm 2 where kC is the magneto-volume coupling constant [1]. The coefficient kC obtained in this way is 2:74 Â 10 À3 m À2 B .…”

Section: Resultsmentioning

confidence: 99%

“…It plays a special role to understand the Invar effect, where the interaction of itinerant magnetism and volume plays a decisive role [1]. The interaction is generalized to the interactions between two fundamental collective excitations: magnon and phonon.…”

Section: Introductionmentioning

confidence: 99%

Phonon softening by magnetic moment in γ‐Fe

Zhang

2011

Journal of Magnetism and Magnetic Materials

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“…Although Fe-Ni alloys demonstrate anomalous thermal behavior with many different compositions (some including additional components such as titanium and manganese), Invar is typically manufactured with weight percentages of 64% Fe and 36% Ni to procure the lowest possible CTE for the binary alloy [ 4 , 5 ]. The thermal expansion attenuation, often referred to as the Invar-effect or magnetostriction, is a result of the magnetic state of the alloy [ 1 , 6 ]. The ferromagnetic state required for magnetostriction only exists below the Curie temperature of Invar [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

Investigating the Linear Thermal Expansion of Additively Manufactured Multi-Material Joining between Invar and Steel

et al. 2020

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This work investigated the linear thermal expansion properties of a multi-material specimen fabricated with Invar M93 and A36 steel. A sequence of tests was performed to investigate the viability of additively manufactured Invar M93 for lowering the coefficient of thermal expansion (CTE) in multi-material part tooling. Invar beads were additively manufactured on a steel base plate using a fiber laser system, and samples were taken from the steel, Invar, and the interface between the two materials. The CTE of the samples was measured between 40 °C and 150 °C using a thermomechanical analyzer, and the elemental composition was studied with energy dispersive X-ray spectroscopy. The CTE of samples taken from the steel and the interface remained comparable to that of A36 steel; however, deviations between the thermal expansion values were prevalent due to element diffusion in and around the heat-affected zone. The CTEs measured from the Invar bead were lower than those from the other sections with the largest and smallest thermal expansion values being 10.40 μm/m-K and 2.09 μm/m-K. In each of the sections, the largest CTE was measured from samples taken from the end of the weld beads. An additional test was performed to measure the aggregate expansion of multi-material tools. Invar beads were welded on an A36 steel plate. The invar was machined, and the sample was heated in an oven from 40 °C and 160 °C. Strain gauges were placed on the surface of the part and were used to analyze how the combined thermal expansions of the invar and steel would affect the thermal expansion on the surface of a tool. There were small deviations between the expansion values measured by gauges placed in different orientations, and the elongation of the sample was greatest along the dimension containing a larger percentage of steel. On average, the expansion of the machined Invar surface was 42% less than the expansion of the steel surface. The results of this work demonstrate that additively manufactured Invar can be utilized to decrease the CTE for multi-material part tooling.

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Invar Alloys

Cited by 7 publications

References 163 publications

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn_1.1Fe_0.9P_1−xGe_xcompounds

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn_1.1Fe_0.9P_1−xGe_xcompounds

Phonon softening by magnetic moment in γ‐Fe

Investigating the Linear Thermal Expansion of Additively Manufactured Multi-Material Joining between Invar and Steel

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Invar Alloys

Cited by 7 publications

References 163 publications

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn1.1Fe0.9P1−xGexcompounds

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn1.1Fe0.9P1−xGexcompounds

Phonon softening by magnetic moment in γ‐Fe

Investigating the Linear Thermal Expansion of Additively Manufactured Multi-Material Joining between Invar and Steel

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Product

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A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn_1.1Fe_0.9P_1−xGe_xcompounds

A structural, magnetic and Mössbauer spectral study of the magnetocaloric Mn_1.1Fe_0.9P_1−xGe_xcompounds