Elastic and Dissipative Properties of Amorphous and Nanocrystalline Mg-Ni-Y Alloy

1998 ◽  
Vol 554 ◽  
Author(s):  
Y. M. Soifer ◽  
N. P. Kobelev ◽  
I. G. Brodova ◽  
A. N. Manukhin ◽  
E. Korin ◽  
...  
Keyword(s):  
Internal Friction ◽  
Melt Spinning ◽  
Young Modulus ◽  
Structural Rearrangement ◽  
X Ray Diffraction ◽  
Nanocrystalline State ◽  
Heating And Cooling ◽  
Vibrating Reed ◽  
Kinetics Of ◽  
Melt Spinning Technique

AbstractThe internal friction and Young's modulus of amorphous Mg84Ni12.5Y3.5 alloy obtained by the melt spinning technique have been measured by a vibrating reed method at frequency of 250 Hz at heating and cooling runs in the temperature range from 300K to 625K.. The crystallization kinetics of the alloy was studied by the calorimetric methods (DSC and DTA). The structure of the samples was determined by the x-ray diffraction technique. The Young modulus measurements have revealed the irreversible multi-step changes (up to 50%) accompanied by the irreversible internal friction peaks. These changes were observed in the same temperature intervals where the anomalies of thermal properties were found out. The results obtained are explained by the structural rearrangement from amorphous to nanocrystalline state during the annealing.

New, Experimental Powder Diffraction Data for Metastable Fe3B Phase Prepared According to ICDD Standards

2010 ◽  
Vol 163 ◽  
pp. 173-176
Author(s):  
Lucjan Pająk ◽  
E. Olszewska ◽  
Stanislaw Pikus ◽  
Grzegorz Dercz ◽  
Józef Rasek
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Melt Spinning ◽  
Powder Diffraction Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lattice Constants ◽  
Graphite Monochromator ◽  
Best Fitting ◽  
Melt Spinning Technique

In the present work X-ray studies were performed on annealed Fe78Nb2B20 amorphous alloy prepared by melt-spinning technique. All the samples were annealed in vacuum for 1 hour at temperatures up to 800°C. For the studied alloy -Fe and Fe2B are the stable, crystalline phases. The -Fe crystallized as the first crystalline phase in the sample annealed at 350°C. On the other hand, metastable Fe3B phase appeared to be stable during annealing in 425-800°C temperature range. The best fitting of the experimental X-ray data to as jet available ICDD files was obtained for Ni3P type structure (39-1315 – S.G.: I (82)). New, experimental powder diffraction data for metastable Fe3B phase prepared according to ICDD standards were elaborated for the sample annealed at 600°C. For this sample the best agreement between the calculated values of lattice constants and positions of experimental diffraction lines was obtained. The X-ray data were collected using X-Pert Philips diffractometer equipped with curved graphite monochromator on diffracted beam. The Treor program was applied for the analysis of X-ray diffraction data.

Recrystallization of Amorphous or Nanocrystalline NdBa2Cu3O7−x and GdBa2Cu3O7−x

1992 ◽  
Vol 275 ◽  
Author(s):  
T. J. Folkerts ◽  
S. I. Yoo ◽  
Youwen Xu ◽  
M. J. Kramer ◽  
K. W. Dennis ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Temperature Xrd ◽  
Melt Spun ◽  
Temperature Heat ◽  
Higher Temperature ◽  
Xrd Studies ◽  
Melt Spinning Technique

ABSTRACTUsing a novel melt-spinning technique, we have produced highly disordered NdBa2Cu3O7−x and GdBa2Cu3Oy−x materials. Samples which were melt-spun in an O2 environment consist of nanocrystals with the tetragonal REBa2Cu3O7−x structure: samples which were processed in an N2 environment consist of an amorphous matrix with small amounts of crystalline BaCu2O2, as shown by x-ray diffraction and electron microscopy. High temperature XRD studies indicate that the BaCu2O2 is eliminated during heating to 500°C in O2 and that the REBa2Cu3O7−x Phase recrystallizes directly from the amorphous matrix at temperatures below 800°C. Preliminary magnetization measurements show that higher temperature heat treatments are needed to restore superconductivity.

Nanocrystallization of Cobalt Based Metallic Glass

2009 ◽  
Vol 67 ◽  
pp. 25-32 ◽  
Author(s):  
A.P. Srivastava ◽  
Dinesh Srivastava ◽  
K.G. Suresh ◽  
G.K. Dey
Keyword(s):  
Metallic Glass ◽  
Melt Spinning ◽  
Amorphous Ribbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Addition ◽  
Isothermal Analysis ◽  
Effect Of Copper ◽  
Melt Spinning Technique

Effect of copper addition in a Metallic glass 2714A on the nanocrystallization characteristics have been examined in this study. Amorphous ribbon of the alloy composition Co64.5 Fe3.5 Si16.5 B13.5 Ni1Cu1 were prepared by melt spinning technique. Nanocrystallization kinetics was studied using differential scanning calorimeter technique. The kinetic parameters such as activation energy and Avrami exponent were determined using two different non-isothermal analysis methods. The kinetic behavior of individual crystallization event has been rationalized on the basis of these results. The role of addition of copper on the crystallization behavior has been understood by comparing with Metallic glass 2714A. The isothermally annealed nanocrystallized microstructures were characterized by X-ray diffraction.

Preferred Orientation in Splat-Quenched Materials

1981 ◽  
Vol 8 ◽  
Author(s):  
N.W. Blake ◽  
F.A. Rames ◽  
R.W. Smith
Keyword(s):  
High Purity ◽  
Melt Spinning ◽  
Preferred Orientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ribbon Plane ◽  
Extreme Degree ◽  
Melt Spinning Technique

ABSTRACTHigh purity, splat-quenched metal ribbons, produced by the melt spinning technique, were examined for preferred orientation using x-ray diffraction. Of the materials tested (Zn, Cd, Ag, Bi, Pb, Sb, Mg, Sn) all except Sn exhibited some degree of preferred orientation in the plane of the metal ribbon. the hcp metals Zn and Cd showed an extreme degree of preferred orientation with the 002 plane being closely parallel to the ribbon plane. The Zn ribbon was analysed more closely with a view to its use as a crystal monochromator for x-ray diffraction. The high purity Zn was found to have some instability of preferred orientation with increase in time and temperature. The orientation was found to be effectively stabilized by the intentional addition of impurities, or by the use of lower purity (99.99%) Zn. In this form, the Zn ribbon could be used as a crystal analyser for x-ray diffraction with both intensity and resolution comparable to that of the 1011 plane in Quartz.

Internal Friction and Elastic Modulus Change Associated with Structural Relaxation and Crystallization in Amorphous Mg-Ni-Y Alloys.

2000 ◽  
Vol 644 ◽  
Author(s):  
Y. M. Soifer ◽  
N. P. Kobelev ◽  
E. Korin ◽  
L. Soifer ◽  
D. Mogilyanskii ◽  
...  
Keyword(s):  
Internal Friction ◽  
Young’S Modulus ◽  
Structural Relaxation ◽  
Intermediate Phase ◽  
Young's Modulus ◽  
Crystallization Kinetic ◽  
Kinetic Studies ◽  
Mechanical Spectroscopy ◽  
Heating And Cooling ◽  
Vibrating Reed

AbstractMechanical spectroscopy technique has been applied to investigation of structural relaxation and crystallization of Mg-Ni-Y amorphous alloys of different composition. The composition of the alloys was varied due to change of yttrium concentration from 0 to 7 at.%. The internal friction (IF) and Young's modulus have been measured by a vibrating reed method at frequency of ∼200 Hz at heating and cooling runs in the temperature range from 300K to 650K. Crystallization kinetic studies of the alloys by DSC and XRD showed that the transition from amorphous to crystalline state in the Mg-Ni-Y alloys has gone through several stages with origination of intermediate phase. IF spectra and Young's modulus of the alloys have been analyzed and the effect of yttrium content on the stability of intermediate phase was investigated.

Fe86.5Zr7B3Cu3.5 Nanocrystalline Ribbon Prepared by Melt – Spinning Technique without Annealing

2007 ◽  
Vol 121-123 ◽  
pp. 1257-1260 ◽  
Author(s):  
Ji Fan Hu ◽  
B. Li ◽  
Hong Wei Qin ◽  
D.L. Zhao ◽  
Y.M. Hao ◽  
...  
Keyword(s):  
Melt Spinning ◽  
X Ray Diffraction ◽  
Saturation Magnetostriction ◽  
Soft Magnetic ◽  
Giant Magnetoimpedance ◽  
X Ray ◽  
Average Grain Size ◽  
Saturation Magnetic Induction ◽  
Melt Spinning Technique ◽  
Nanocrystalline Ribbon

Fe86.5Zr7B3Cu3.5 nanocrystalline ribbon can be directly fabricated by melt – spinning technique with an appropriate quenching speed without annealing processes. The average grain size of α-Fe for Fe86.5Zr7B3Cu3.5 as quenched ribbon prepared with a quenched speed V=40 m/s is about 10-13 nm estimated from X-ray diffraction and TEM observation. For Fe86.5Zr7B3Cu3.5 nanocrystalline as quenched ribbon (V=40m/s), the saturation magnetic induction Bs is 1.47 T, permeability μe at 1 kHz is 25600 and saturation magnetostriction λs is -2×10-6. The magnetoimpedance value Z/Z0 of the Fe86.5Zr7B3Cu3.5 nanocrystalline as quenched ribbon reaches –38.32 % under H=7162 A/m. Our present results reveal a novel route to fabricate the nanocrystaline ribbons with excellent soft magnetic properties and giant magnetoimpedance.

Microstructural analysis for Sn-Bi-Sb-In alloy prepared by rapid solidification

2016 ◽  
Vol 12 (2) ◽  
pp. 4244-4254
Author(s):  
Sara Mosaad Mahlab ◽  
Mustafa Kamal ◽  
Abd El-Raouf Mansour
Keyword(s):  
Electron Microscopy ◽  
Microstructure Evolution ◽  
Melt Spinning ◽  
Vickers Microhardness ◽  
Microstructural Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapidly Solidified ◽  
Melt Spinning Technique ◽  
Scanning Electron

In the present study, Sn70-X at.% -Bi15 at.% -Sb15 at.%- Inx at.%  alloy ( x= 0, 2, 4, 6),  were prepared by melt spinning technique. Optical microscopy, scanning electron microscopy combined with energy dispersive X-ray analysis (SEM-EDX), X-ray diffraction analysis (XRD), and Vickers microhardness (Hv); were used to characterize the phase transformation and the microstructure evolution. The results contribute to the understanding of the microstructure evolution in alloys of the type prepared by melt spinning technique. This work reports on a comparative study of the rapidly solidified, in order to compare the microhardness and microstructural analysis. 

Solidification Behaviour of Al Particles Embedded in an Ni Aluminide Matrix

1995 ◽  
Vol 398 ◽  
Author(s):  
K.A.Q O'Reilly ◽  
W.T. Kim ◽  
B. Cantor
Keyword(s):  
Grain Boundaries ◽  
Melt Spinning ◽  
Contact Angles ◽  
Nucleation Kinetics ◽  
Spherical Cap ◽  
Rich Phase ◽  
Heating And Cooling ◽  
Transmission Electron ◽  
Cap Model ◽  
Kinetics Of

ABSTRACTA hypereutectic Al-40wt%Ni alloy has been manufactured by melt spinning, and the resulting microstructure examined by transmission electron microscopy. As-melt spun hypereutectic Al-40wt%Ni consists of an Ni aluminide matrix and an A1-rich phase distributed in the form of particles with sizes ∼ 50-100 nm, and as an irregular layer at the cell and grain boundaries. Diffraction analysis of the Ni aluminide matrix is consistent with the ASTM x-ray diffraction standard 2θ values for the orthorhombic NiAl3 phase, a=6.6114 Å, b=7.3662 Å andc=4.8112 Å. The solidification nucleation kinetics of Al-rich particles have been examined by heating and cooling experiments in a differential scanning calorimeter over a range of heating and cooling rates. Solidification of the Al-rich phase at the cell and grain boundaries nucleates catalytically on the surrounding Ni aluminide matrix at an undercooling of ∼ 3 K. Analysis of the solidification nucleation kinetics of the Al-rich phase in Al-40wt%Ni supports the hypothesis [1-4] that the classical spherical cap model of heterogeneous nucleation breaks down at low undercoolings and small contact angles.

Eutectoid Transformation in Zn-Al Alloys Solidified by Rapid Cooling

2014 ◽  
Vol 790-791 ◽  
pp. 223-228 ◽  
Author(s):  
Ildiko Peter ◽  
Béla Varga ◽  
Mario Rosso
Keyword(s):  
Melt Spinning ◽  
Al Alloys ◽  
Eutectoid Temperature ◽  
Microcrystalline Structure ◽  
X Ray Diffraction ◽  
Alloying Element ◽  
Volume Changes ◽  
X Ray ◽  
Kinetic Effects ◽  
Melt Spinning Technique

Rapid solidification represents a very attractive approach to develop new Al alloys in an economically convenient way. The lower segregation content, refined grains, higher ultimate tensile and yield strengths combined to a good ductile properties confer to these materials an interesting position also in the so critical automotive and/or aeronautical applications. The current paper presents results of an analysis concerning Zn-Al alloys with a new metastable microcrystalline structure, where Copper has been used as alloying element. With addition of elements as Ti and B modification of the microstructure has been reached. In order to study the influence of the cooling rate on the microstructure and structural transformations castings has been realized with melt spinning technique, in both steel and sand moulds. For morphological investigations optical and scanning electron microscopy has been employed. By dilatometric analysis and X-Ray diffraction technique the thermodynamic factors, the kinetic effects, phase transformations and the volume changes related to the transformations produced at the eutectoid temperature have been monitored. For the aforementioned field of applications the most favourable composition has been chosen: based on the up to date outcomes, by modifying the original alloy with some elements a quite homogeneous structure combined with good mechanical behaviour has been obtained.

Effect of Crystallization on the Electrical Resistance and Structure of Amorphous Fe-Co-Cr-B-Si Alloys / Wpływ Krystalizacji Na Oporność Elektryczną I Strukturę Amorficznych Stopów Fe-Co-Cr-B-Si

2012 ◽  
Vol 57 (4) ◽  
pp. 1031-1039
Author(s):  
H. Solomon ◽  
N. Solomon
Keyword(s):  
Electrical Resistivity ◽  
Electrical Properties ◽  
Amorphous Alloys ◽  
Melt Spinning ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Investigation Methods ◽  
Melt Spinning Technique

The goal of this paper is to present the influence of temperature variation and iron substitution with Co on the structure and electrical properties of amorphous Fe75-xCoxCr1B7Si17 alloys (where x=1, 4, 7, and 10 at.%), obtained by melt-spinning technique. The electrical resistivity of the samples was measured by using a usual four-probe method from -160°C to 750°C. The electrical resistivity was also measured at room temperature for the amorphous Fe75-xCoxCr1B7Si17 ribbons annealed at various temperatures for different holding time. The annealed samples were also investigated by Vickers microhardness test. The amorphous structure of tested materials was examined by X-ray diffraction (XRD), Mossbauer spectroscopy, differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) methods. Experimental results confirmed the utility of applied investigation methods and the influence of the Co content and annealing process on the crystallization, structure and electrical properties of examined amorphous alloys.

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