Characterization of Martensitic Transformation in Ferromagnetic Shape Memory Alloys Co-Ni-Ga Melt-Spun Ribbons

2005 ◽  
Vol 475-479 ◽  
pp. 2033-2036 ◽  
Author(s):  
F.B. Meng ◽  
Yang Xian Li ◽  
H.Y. Liu ◽  
J.P. Qu ◽  
M. Zhang ◽  
...  
Keyword(s):  
Martensitic Transformation ◽  
Structural Transition ◽  
Magnetic Measurements ◽  
The Body ◽  
Lattice Parameters ◽  
X Ray Diffraction ◽  
Diffraction Intensity ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory

The martensitic transformation in Co50Ni20Ga30 ribbon has been characterized in detail by means of X-ray diffraction and magnetic measurements. The sample showed a structural transition from the body-centered cubic with indexed lattice parameters of a=5.743 Å to martensite with a tetragonal structure with lattice parameters of a=b=5.422 Å and c=6.401 Å. (c/a>1). By comparing the results of the diffraction intensity and the magnetic susceptibility measurements, we found that the proceeding of the martensitic transformation can be divided into several different steps during cooling from 283 K to 213 K. During heating from 673 K to 833 K, the peak width became very wide and the intensity became very low. It reveals an order-disorder transformation.

Martensitic Transformation and Crystal Structure Characterization of Ni-Fe-Ga-Co Ferromagnetic Shape Memory Alloys

2016 ◽  
Vol 879 ◽  
pp. 2061-2065
Author(s):  
Pan Jiang ◽  
Jing Bai ◽  
Pu Wei ◽  
Shuang Ji Han ◽  
Mei Jie Yang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Martensitic Transformation ◽  
Transformation Temperature ◽  
Structure Characterization ◽  
Second Phase ◽  
Martensitic Transformation Temperature ◽  
Ferromagnetic Shape Memory Alloys ◽  
Ferromagnetic Shape Memory ◽  
Martensitic Lath

In this paper, the martensitic transformation temperature, the microstructure and the crystal structure of the complicated martensitic phases of Ni56-xFe19Ga25Cox (x =0, 1.5, 3, 4.5, 6) alloys were investigated by DSC, XRD, SEM and TEM techniques. DSC results show that the martensitic transformation temperature Tm, which is above the room temperature, decreases with the increasing Co content. The microstructure of the Ni56-xFe19Ga25Cox (x =0, 1.5, 3, 4.5, 6) alloys is composed by the martensitic lath and randomly distributed γ phase. The 6M+14M mixed modulated martensite and the γ second phase were detected in the Ni53Fe19Ga25Co3 alloy by XRD and TEM tests.

The Synthesis of Ce-Filled CoSb3 and Characterization of its Magnetic and Structural Properties

2003 ◽  
Vol 793 ◽  
Author(s):  
Arwyn L. E. Smalley ◽  
Brandon Howe ◽  
David C. Johnson
Keyword(s):  
Low Temperatures ◽  
Magnetic Measurements ◽  
Rietveld Analysis ◽  
X Ray Diffraction ◽  
Electrical Measurements ◽  
X Ray ◽  
Ferromagnetic Component ◽  
Phase Pure ◽  
Powder Samples

ABSTRACTA series of cerium-containing CoSb3 samples were synthesized, with cerium quantities varying from 0 to 2 stoichiometric equivalents. These samples were annealed at low temperatures to crystallize the kinetically stable phases CexCo4Sb12 (x = 0–0.5). X-ray diffraction showed that these samples were phase pure, and Rietveld analysis on x-ray diffraction data from powder samples indicated that these samples were 25–88% crystalline. Electrical measurements showed that these samples are n-type, which was previously unknown in CexCo4Sb12. Magnetic measurements showed that the samples were paramagnetic due to the cerium being incorporated into the diamagnetic CoSb3 compound. In addition, they contained a ferromagnetic component that was attributed to the amorphous, cerium-containing phase.

The Phase Transformation and Magnetic Properties in Ni-Mn-In Alloys

2013 ◽  
Vol 712-715 ◽  
pp. 54-57 ◽  
Author(s):  
Hai Le Yan ◽  
Zong Bin Li ◽  
Chun Yang Zhang ◽  
Yu Dong Zhang ◽  
Claude Esling ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Phase Transformation ◽  
Structural Transition ◽  
Alloy Composition ◽  
Ferromagnetic Shape Memory Alloys ◽  
Scanning Calorimetry ◽  
Phase Transition Temperatures ◽  
Ferromagnetic Shape Memory ◽  
Curie Temperatures ◽  
Magnetization Change

The phase transformation and magnetic properties of Heusler-type Ni50Mn50-xInx(x=10~16) ferromagnetic shape-memory alloys have been systemically investigated by differential scanning calorimetry and vibrating sample magnetometry. It is found that the phase transition temperatures show a linear relationship with the In concentration and the curie temperatures of austenite phases are not sensitive to the alloy composition. The existence of large magnetization change during the magneto-structural transition is the origin of magnetic-field-induced transformation effect.

Structural Characterization of Co70-xNixGa30 Ferromagnetic Shape Memory Alloys

2008 ◽  
Vol 52 ◽  
pp. 103-108 ◽  
Author(s):  
Sidananda Sarma ◽  
A. Srinivasan
Keyword(s):  
Magnetic Susceptibility ◽  
Shape Memory ◽  
Room Temperature ◽  
Structural Parameters ◽  
Ac Magnetic Susceptibility ◽  
X Ray Diffraction ◽  
Ferromagnetic Shape Memory Alloys ◽  
Two Phase ◽  
X Ray ◽  
Ferromagnetic Shape Memory

Polycrystalline ingots of Co70–xNixGa30 (20 ≤ x ≤ 26) ferromagnetic shape memory alloy (FSMA) were prepared by arc melting elemental powders followed by homogenization at 1230 °C for 24 hrs and quenching in liquid nitrogen. Room temperature X-Ray diffraction (XRD) patterns of as-quenched samples exhibited single-phase tetragonal structure for alloy compositions with x = 21 to 26, and a two-phase structure (cubic A2-phase along with weak tetragonal phase) for the alloy with x = 20. Rietveld refinement was performed on the X-ray diffraction patterns to obtain the refined structural parameters. Differential Scanning Calorimeter (DSC) curves recorded from 30 °C to 250 °C revealed martensite-austenite and austenite-martensite transformations in all alloys except the alloy with composition x = 20. Low temperature ac magnetic susceptibility measurements confirmed the existence of martensitic transformations in the alloy with x = 20. The structural transformation temperatures show a linear variation with e/a ratio. All the alloys were ferromagnetic at room temperature. Curie temperature was determined using a high temperature ac magnetic susceptibility measurement set-up.

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