MARTENSITIC TRANSFORMATION AND MAGNETIC PROPERTIES OF Fe-Pd ALLOYS

1993 ◽  
Vol 07 (01n03) ◽  
pp. 794-797
Author(s):  
T. GOTO ◽  
A. KASHIWAKURA ◽  
S. KOYAMA
Keyword(s):  
Magnetic Properties ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Transformation Temperature ◽  
Composition Range ◽  
Internal Field ◽  
Temperature Curve ◽  
Mossbauer Spectrum ◽  
Broad Maximum ◽  
The Difference

The effects of martensitic transformation from fcc to fct structure on the magetic properties of Fe-Pd alloys are investigated by magnetization, magnetostriction and 57Fe Mössbauer effect measurements. In the composition range of 30–32.5 at .% Pd, in which the fcc-fct transformation occurs, the Curie temperature decreases sharply with decreasing Pd content and the magnetostriction vs. temperature curve has a broad maximum around the fcc-fct transformation temperature. The Mössbauer spectrum exhibits the difference between the internal field for fcc, and fct.

Martensitic Transformation and Mechanical Properties of Fe-Doped Ni54Mn21Ga25 Alloys

2011 ◽  
Vol 687 ◽  
pp. 500-504
Author(s):  
S. X. Xue ◽  
S.S. Feng ◽  
P. Y. Cai ◽  
Q T Li ◽  
H. B. Wang
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Magnetic Properties ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Directional Solidification ◽  
Transformation Temperature ◽  
Room Temperature ◽  
Martensitic Transformation Temperature ◽  
Polycrystalline Alloys

Ni54Mn21-xFexGa25（x=0,1,3,5,7,9）polycrystalline alloys were prepared by the technique of directional solidification and the effect of substituting Fe for Mn on the martensitic transformation and mechanical properties of the alloys was analyzed. It was found that the Curie temperature increased with increasing substitution while the martensitic transformation temperature decreased. The Fe-doped Ni54Mn21Ga25 alloys exhibit excellent magnetic properties at room temperature; the typical Ni54Mn20Fe1Ga25 alloy shows a large magnetic-induced-strain of -1040 ppm at a magnetic field of 4000 Oe.

scholarly journals Full Variation of Site Substitution in Ni-Mn-Ga by Ferromagnetic Transition Metals

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 850
Author(s):  
Vít Kopecký ◽  
Michal Rameš ◽  
Petr Veřtát ◽  
Ross H. Colman ◽  
Oleg Heczko
Keyword(s):  
Transition Temperature ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Transformation Temperature ◽  
Bulk Material ◽  
Martensitic Transition ◽  
Ferromagnetic Transition ◽  
Transition Elements ◽  
Martensitic Transformation Temperature ◽  
Valence Electrons

Systematic doping by transition elements Fe, Co and Ni on each site of Ni2MnGa alloy reveal that in bulk material the increase in martensitic transformation temperature is usually accompanied by the decrease in ferromagnetic Curie temperature, and vice versa. The highest martensitic transformation temperature (571 K) was found for Ni50.0Mn25.4(Ga20.3Ni4.3) with the result of a reduction in Curie temperature by 55 K. The highest Curie point (444 K) was found in alloy (Ni44.9Co5.1)Mn25.1Ga24.9; however, the transition temperature was reduced to 77 K. The dependence of transition temperature is better scaled with the Ne/a parameter (number of non-bonding electrons per atom) compared to usual e/a (valence electrons per atom). Ne/a dependence predicts a disappearance of martensitic transformation in (Ni45.3Fe5.3)Mn23.8Ga25.6, in agreement with our experiment. Although Curie temperature usually slightly decreases while the martensitic transition increases, there is no significant correlation of Curie temperature with e/a or Ne/a parameters. The doping effect of the same element is different for each compositional site. The cascade substitution is discussed and related to the experimental data.

scholarly journals Tunable Martensitic Transformation and Magnetic Properties of Sm-Doped NiMnSn Ferromagnetic Shape Memory Alloys

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1115
Author(s):  
Najam ul Hassan ◽  
Mohsan Jelani ◽  
Ishfaq Ahmad Shah ◽  
Khalil Ur Rehman ◽  
Abdul Qayyum Khan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Transformation Temperature ◽  
Room Temperature ◽  
Field Variation ◽  
Martensitic Transformation Temperature ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory

NiMnSn ferromagnetic shape memory alloys exhibit martensitic transformation at low temperatures, restricting their applications. Therefore, this is a key factor in improving the martensitic transformation temperature, which is effectively carried out by proper element doping. In this research, we investigated the martensitic transformation and magnetic properties of Ni43Mn46-x SmxSn11 (x = 0, 1, 2, 3) alloys on the basis of structural and magnetic measurements. X-ray diffraction showed that the crystal structure transforms from the cubic L21 to the orthorhombic martensite and gamma (γ) phases. The reverse martensitic and martensitic transformations were indicated by exothermic and endothermic peaks in differential scanning calorimetry. The martensitic transformation temperature increased considerably with Sm doping and exceeded room temperature for Sm = 3 at. %. The Ni43Mn45SmSn11 alloy exhibited magnetostructural transformation, leading to a large magnetocaloric effect near room temperature. The existence of thermal hysteresis and the metamagnetic behavior of Ni43Mn45SmSn11 confirm the first-order magnetostructural transition. The magnetic entropy change reached 20 J·kg−1·K−1 at 266 K, and the refrigeration capacity reached ~162 J·Kg−1, for Ni43Mn45SmSn11 under a magnetic field variation of 0–5 T.

Suppression of Ferromagnetism in EuxCa1-xB6

2012 ◽  
Vol 190 ◽  
pp. 97-100 ◽  
Author(s):  
V.V. Glushkov ◽  
A.V. Kuznetsov ◽  
I. Sannikov ◽  
A.V. Bogach ◽  
S.V. Demishev ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Curie Temperature ◽  
Single Crystals ◽  
Effective Magnetic Moment ◽  
Paramagnetic State ◽  
Low Field ◽  
Wide Range ◽  
Free Ion ◽  
The Eu

We report the magnetic properties of EuxCa1-xB6 single crystals (0.756x1) studied in the wide range of temperatures (1.8-300 K) and magnetic fields (up to 50 kOe). It was found that low field magnetic susceptibility χ (T) follows the Curie-Weiss law χ~(T-Θp)-1 at high temperatures for all the concentrations studied. The effective magnetic moment of the Eu2+ ion estimated from the data diminishes from the free ion value μeff7.93μB (μB - Bohr magneton) for x=1 to μeff7.3μB for x=0.756. A universal behavior of magnetic susceptibility χ~(T-Θ)-α (α=1.5) is detected close to the Curie temperature TC in the paramagnetic state at both metallic (x>xC~0.8) and dielectric (xC.

The Effect of Cobalt on Martensitic Toughening Parameters in NiAl

1988 ◽  
Vol 133 ◽  
Author(s):  
Scott M. Russell ◽  
C. C. Law ◽  
M. J. Blackburn
Keyword(s):  
Martensitic Transformation ◽  
Ambient Temperature ◽  
Transformation Temperature ◽  
Transformation Strain ◽  
Temperature Hysteresis ◽  
Transformation Toughening ◽  
Strain Anisotropy ◽  
Interfacial Mobility

ABSTRACTThe martensitic transformation and the effect of cobalt additions on important martensitic toughening parameters are being studied as a means of toughening NiAl alloys. Cobalt additions to NiAl martensite are seen to lower the Ms temperature, reduce the transformation strain anisotropy, and reduce the transformation temperature hysteresis (an indicator of interfacial mobility). Optimization of these parameters should allow martensitic transformation toughening processes to aid in overcoming the ambient temperature brittleness of NiAl alloys.

Effect of Thickness on Mechanically Tunable Magnetic Anisotropy of FeGa Thin Films Deposited on Flexible Substrates

2015 ◽  
Vol 815 ◽  
pp. 227-232 ◽  
Author(s):  
Ying Yu ◽  
Shu Hong Xie ◽  
Qing Feng Zhan
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Effective Strain ◽  
Anisotropy Field ◽  
Saturation Field ◽  
Effective Anisotropy ◽  
Magnetostriction Constant ◽  
The Difference ◽  
Different Strains

A practical way to manipulate the magnetic anisotropy of magnetostrictive FeGa thin films grown on flexible polyethylene terephthalate (PET) substrates is introduced in this study. The effect of film thickness on magnetic properties and magnetostriction constant of polycrystalline FeGa thin films was investigated. The anisotropy field Hk of flexible FeGa films, i.e., the saturation field determined by fitting the hysteresis curves measured along the hard axis, was enhanced with increasing the tensile strain applied along the easy axis of the thin films, but this enhancement via strain became unconspicuous with increasing the thickness of FeGa films. In order to study the magnetic sensitivity of thin films responding to the external stress, we applied different strains on these films and measure the corresponding anisotropy field. Moreover, the effective magnetostriction constant of FeGa films was calculated from the changes of both anisotropy field and external strain based on the Villari effect. A Neel’s phenomenological model was developed to illustrate that the effective anisotropy field of FeGa thin films was contributed from both the constant volume term and the inverse thickness dependent surface term. Therefore, the magnetic properties for the volume and surface of FeGa thin films were different, which has been verified in this work by using vibrating sample magnetometer (VSM) and magneto-optic Kerr effect (MOKE) system. The anisotropy field contributed by the surface of FeGa film and obtained by MOKE is smaller than that contributed by the film volume and measured by VSM. We ascribed the difference in Hk to the relaxation of the effective strain applied on the films with increasing the thickness of films.

Sign in / Sign up

Export Citation Format

Share Document