The Reconstructive Crystal Structure and the Exchange Energy

2006 ◽  
Vol 966 ◽  
Author(s):  
Ahmad Yazdani ◽  
Reza Osati Araghi ◽  
Farid Arya
Keyword(s):  
Electrical Resistivity ◽  
Magnetic Transition ◽  
Resistivity Measurement ◽  
Stable State ◽  
Electrical Resistivity Measurement ◽  
X Ray ◽  
Resistivity Measurements ◽  
Pattern Change ◽  
Field Independent

ABSTRACTIn order to describe the role of temperature variation on suppress of broad range of magnetic transition, the effect of annealing on different samples of a Gd-based intermetallic compound (i.e., Gd2Au) is investigated. The X-ray, AC and D.C susceptibility and electrical resistivity measurements for different annealed samples revealed that: (i) A great exchange dispersion is observed in A.C susceptibility (ii) This unstable exchange can be stabilized at certain annealing temperature, where the short rang unstable Ferromagnetic (F.M) breaks down or even changes to an Antiferromagnetic (AF.M) stable state. (iii) The DC susceptibility shows a spin-glass like transition temperature at TN= 61 K, above which the compound exhibits a completely paramagnetic (P.M) behavior and is field independent. (iv) the iso-termal magnetization does not follow the field induced transition (F.I.T) and behaves completely as a paramagnet which is independent of the field up to the highest available fields. The electrical resistivity measurement shows: a) A pronounced sharp bend at TN=61 K is manifested in ρ(T). b)some strong peak of X-ray pattern change into double adjacent lines in some intervals of low temperatures

scholarly journals Tracing Microalloy Precipitation in Nb-Ti HSLA Steel During Austenite Conditioning

2020 ◽  
Author(s):  
Johannes Webel ◽  
Adrian Herges ◽  
Dominik Britz ◽  
Eric Detemple ◽  
Volker Flaxa ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Ion Beam ◽  
Hsla Steel ◽  
Isothermal Holding ◽  
Resistivity Measurement ◽  
Hot Working ◽  
Electrical Resistivity Measurement ◽  
Steel Matrix ◽  
Finished Steel ◽  
Resistivity Measurements

Microalloying of low carbon steel with niobium (Nb) and titanium (Ti) is standardly applied in high-strength low-alloy (HSLA) steels enabling austenite conditioning during thermo-mechanical controlled processing (TMCP), which results in pronounced grain refinement in the finished steel. The metallurgical effects of microalloying elements are related solute drag and precipitate particle pinning, both acting on the austenite grain boundary thereby delaying or suppressing recrystallization of the deformed grain. In that respect it is important to better understand the precipitation kinetics as well as the precipitation sequence in a typical Nb-Ti-microalloyed steel. Various characterization methods have been utilized in this study for tracing microalloy precipitation after simulating different austenite TMCP conditions in a Gleeble apparatus. Atom probe tomography (APT), scanning transmission electron microscopy in a focused ion beam equipped scanning electron microscope (STEM-on-FIB) and electrical resistivity measurements provide complementary information on the precipitation status and are correlated with each other. It will be demonstrated that accurate electrical resistivity measurements can monitor the general consumption of solute microalloys (Nb) during hot working which was complemented by APT measurements of the steel matrix. On the other hand, STEM revealed that a large part of Nb-containing particles during hot working are co-precipitated with titanium during cooling from the austenitizing temperature. Precipitates that form during cooling or isothermal holding can be distinguished from strain-induced precipitates by corroborating STEM measurements with APT results. APT specifically allows obtaining detailed information about the chemical composition of precipitates as well as the distribution of elements inside the particle. Electrical resistivity measurement, on the contrary, provides macroscopic information on the progress of precipitation and can be calibrated by APT. The current paper highlights the complementarity of these methods and shows first results within the framework of a larger study on strain-induced precipitation.

scholarly journals Theoretical Study on Geometries of Electrodes in Laboratory Electrical Resistivity Measurement

2019 ◽  
Vol 9 (19) ◽  
pp. 4167 ◽  
Author(s):  
Hong ◽  
Chong ◽  
Cho
Keyword(s):  
Electrical Resistivity ◽  
Multiple Scales ◽  
Design Method ◽  
Resistivity Measurement ◽  
Experimental Tests ◽  
Field Resistance ◽  
Electrode Spacing ◽  
Electrical Resistivity Measurement ◽  
Resistivity Measurements ◽  
Complementary Study

Electrical resistivity tests have been widely conducted in multiple scales, from a few centimeters to kilometers. While electrode spacing is used to define field resistance, laboratory measurements in a limited space need to consider electrode geometry. However, there are no studies that theoretically explore the effects of the geometries of electrodes and container size on laboratory electrical resistivity measurements. This study formulates a theoretical electrical resistance for the geometry of cylindrical electrodes and the size of a non-conductive container with the method of image charges. As a complementary study, experimental tests were conducted to verify the derived equations. The discussion includes the concepts of the spherical equivalent electrodes and a simple design method for container size.

Transformation Behavior of a Ti-Ni-Cu-Fe Alloy

2004 ◽  
Vol 449-452 ◽  
pp. 185-188 ◽  
Author(s):  
Tae Hyun Nam ◽  
Tae Yeon Kim ◽  
Ji Soon Kim ◽  
Seung Baik Kang
Keyword(s):  
Differential Scanning Calorimetry ◽  
Electrical Resistivity ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Scanning Calorimetry ◽  
X Ray

Transformation behavior of a Ti-43.0Ni-5.0Cu-2.0Fe(at%) alloy has been investigated by means of electrical resistivity measurement, differential scanning calorimetry and X-ray diffraction. The alloy transformed in three-stage during each cooling and heating procedure. That is, the B2-R-B19-B19' on cooling and the B19'-B19-R-B2 on heating.

Comparison of temperature driven ordering in bulk foil and thin film of L10ordered FePd

2004 ◽  
Vol 842 ◽  
Author(s):  
Chaisak Issro ◽  
Wolfgang Püschl ◽  
Wolfgang Pfeiler ◽  
Bogdan Sepiol ◽  
Peter F. Rogl ◽  
...  
Keyword(s):  
Thin Film ◽  
Electrical Resistivity ◽  
Long Range ◽  
Molecular Beam ◽  
Resistivity Measurement ◽  
Range Order ◽  
Electrical Resistivity Measurement ◽  
Long Range Order ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTChanges in the degree of long-range order of 10 μm thick FePd foil are presented and compared with results on 50 nm thick FePd films. The films were produced by dc and rf magnetron co-sputtering on Si as well as by molecular beam epitaxy co-deposition on MgO substrates. Long-range order was studied by electrical resistivity measurement, X-ray diffraction and Möβbauer spectroscopy.

Effect of Thermal Cycling on Transformation Behavior of Ti–24Nb–1Mo Alloy (at.%)

2020 ◽  
Vol 20 (11) ◽  
pp. 6792-6796
Author(s):  
Jin-Hwan Lim ◽  
Mi-Seon Choi ◽  
Tae-Hyun Nam
Keyword(s):  
Electrical Resistivity ◽  
Martensitic Transformation ◽  
Thermal Cycling ◽  
Volume Fraction ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
X Ray Diffraction ◽  
Transformation Behavior ◽  
Thermally Induced ◽  
X Ray

The effect of thermal cycling on the transformation behavior of a Ti–24Nb–1Mo alloy was investigated by means of electrical resistivity measurement, transmission electron microscopy (TEM), X-ray diffraction (XRD), tensile test and Vickers hardness tests. Electrical resistivity changes were not observed in all alloys. It indicates that thermally induced martensitic transformation does not take place in the alloys. After thermal cycling between 298 K and 77 K, clear X-ray diffraction peaks corresponding to ωath phase, which did not exist before thermal cycling, were observed. Volume fraction of ωath phase increased as increasing the number of thermal cycling. ωath phase formed during thermal cycling increased hardness of the alloy. Although thermally induced martensitic transformation did not occur in the alloys, superelastic deformation behavior was observed in the alloys. The superelastic recovery ratio decreased from 81% to 41% by increasing the number of thermal cycling, which came from the increase in the volume fraction of ωath phase.

scholarly journals Selection of electrodes for the ˝in situ˝ electrical resistivity measurements of molten aluminium

2013 ◽  
Vol 49 (3) ◽  
pp. 279-283 ◽  
Author(s):  
M. Petric ◽  
S. Kastelic ◽  
P. Mrvar
Keyword(s):  
Electrical Resistivity ◽  
Contact Resistance ◽  
Electrode Material ◽  
Aluminium Alloys ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
Measuring Cell ◽  
Resistivity Measurements ◽  
Selection Of

The aim of this paper is the selections of proper electrode material for four-probe technique electrical resistivity measurement of aluminium and aluminium alloys. The biggest problem of electrodes is oxidation during measurement causing high contact resistance and giving wrong results. Various materials have been tested and aluminium electrodes have been chosen. Advantage of aluminium electrodes is that they are melted in specimen right after the pouring and causing no interface which is resulting with any contact resistance. The device together with measuring cell for ?in situ? measurement of electrical resistivity was developed using four-probe DC technique.

Formation of Dislocations in NiAl Single Crystals Studied by In Situ Electrical Resistivity Measurement

1997 ◽  
Vol 500 ◽  
Author(s):  
Y. Q. Sun ◽  
P. M. Hazzledine ◽  
D. M. Dimiduk
Keyword(s):  
Electrical Resistivity ◽  
Single Crystals ◽  
Yield Point ◽  
Resistivity Measurement ◽  
Electrical Resistivity Measurement ◽  
Plastic Yielding ◽  
Resistivity Measurements ◽  
Density Of Dislocations ◽  
Abrupt Jump

ABSTRACTThis paper reports experiments in which in situ electrical resistivity measurements were used to monitor the formation of dislocations in initially dislocation-free NiAl single crystals. The electrical resistivity is found to exhibit an abrupt jump at the onset of plastic yielding. This is interpreted to result from an abrupt nucleation of a massive density of dislocations at the yield point.

STUDY OF THE DEPENDENCE OF HIGH Tc ON VARIOUS SINTERING TEMPERATURES FOR Bi-Pb-Sr-Ca-Cu-O SUPERCONDUCTORS

1991 ◽  
Vol 05 (24n25) ◽  
pp. 1635-1638
Author(s):  
S.M. M.R. NAQVI ◽  
A.A. QIDWAI ◽  
S.M. ZIA-UL-HAQUE ◽  
FIROZ AHMAD ◽  
S.D.H. RIZVI ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Liquid Nitrogen ◽  
X Ray Diffraction ◽  
High Tc ◽  
X Ray ◽  
Resistivity Measurements ◽  
Zero Resistance

Bi1.7-Pb0.3-Sr2-Ca2-Cu3-Ox superconducting samples were prepared at 855°C, 862 C, 870 C, and 882 C sintering temperatures respectively. All samples were sintered for 120 hours. The samples were then quenched in liquid nitrogen. The electrical resistivity measurements showed that the samples sintered at 870° C had the best Tc. For these samples the Tc onset was around 120 K and the zero resistance was obtained at 108 K. X-ray diffraction studies showed that the samples were multiphased.

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