Mechanical Properties of Ordered Fe-Al-X Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
Ujjwal Prakash ◽  
Robert A. Buckley ◽  
Howard Jones
Keyword(s):  
Electron Microscopy ◽  
Melt Spinning ◽  
Composition Range ◽  
Tensile Fracture ◽  
Strengthening Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Heat Treated ◽  
Rapidly Solidified

ABSTRACTFe-Al-X alloys (X = Cr, Mo) in the composition range 50 to 80 at. % Fe, 0 to 20 at. % X were rapidly solidified by chill-block melt-spinning. As-spun and heat treated ribbons were characterised by optical and electron microscopy and X-ray diffraction. Strengthening mechanisms were identified using microhardness measurements. Tensile fracture surfaces of ribbons reveal ductile to cleavage to intergranular fracture transitions with increasing Al-content. An increasing preponderance of cleavage fracture with increasing ternary substitution for Fe was observed.

A microstructural characterization of Co-Zr type permanent-magnet materials

1991 ◽  
Vol 49 ◽  
pp. 782-783
Author(s):  
K. R. Lawless ◽  
G. C. Hadjipanayis
Keyword(s):  
Melt Spinning ◽  
Microstructural Characterization ◽  
X Ray Diffraction ◽  
Ion Milling ◽  
X Ray ◽  
Heat Treated ◽  
Diffraction Patterns ◽  
Rapidly Solidified ◽  
Hard Magnetic Properties

Considerable interest has been shown recently in the hard magnetic properties of Co-Zr, Co-Zr-B, and Co-Hf-B alloys, but as yet no detailed microstructural studies have been published. The Co-Zr phase diagram seems to be reasonably well known, although the crystal structure of the Co11Zr2 phase is only partially determined. This paper will report on some preliminary studies of rapidly solidified Co-Zr-B-Si and Co-Hf-B-Si alloys and binary Co-Zr alloys.All specimens used in this study were prepared by melt spinning. Specific alloys were heat treated at temperatures from 650 to 900°C. TEM specimens were prepared from ribbon material by ion milling.X-ray diffraction studies of these alloys all showed a characteristic broad peak centered around d = 0.205nm. Although it was obvious that this was a complex peak, attempts to deconvolute it were unsuccessful. SAD patterns revealed that major phases in the alloys were very heavily faulted, thus giving rise to the very confusing X-ray diffraction patterns.

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. 

Copper(I) Halide Nanoparticle-dispersed Glasses Prepared by Copper Staining

2005 ◽  
Vol 20 (9) ◽  
pp. 2480-2485 ◽  
Author(s):  
Kohei Kadono ◽  
Tatsuya Suetsugu ◽  
Takeshi Ohtani ◽  
Toshihiko Einishi ◽  
Takashi Tarumi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Surface Region ◽  
Borosilicate Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Depth Profiles ◽  
Transmission Electron ◽  
Heat Treated ◽  
Glass Heat

Copper(I) chloride and bromide nanoparticle-dispersed glasses were prepared by means of a conventional copper staining. The staining was performed by the following process: copper stain was applied on the surfaces of Cl−- or Br−-ion-containing borosilicate glasses, and the glasses were heat-treated at 510 °C for various times. Typical exciton bands observed in the absorption spectra of the glasses after the heat treatment indicated that CuCl and CuBr particles were formed in the surface region of the glasses. The average sizes of the CuCl and CuBr particles in the glasses heat-treated for 48 h were estimated at 4.8 and 2.7 nm, respectively. The nanoparticles were also characterized by x-ray diffraction and transmission electron microscopy. Depth profiles of Cu and CuBr concentration in the glass heat-treated for 48 h were measured. Copper decreased in concentration monotonously with depth, reaching up to 60 μm, while the CuBr concentration had a maximum at about 25 μm in depth.

Structure of CoxAg100-x and Its Relation to GMR

1992 ◽  
Vol 286 ◽  
Author(s):  
John Q. Xiao ◽  
J. Samuel ◽  
C. L. Chien
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Composition Range ◽  
Magnetic Scattering ◽  
Granular System ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Concentration

ABSTRACTWe have studied the structure of the Co-Ag granular system across the entire composition range, as well as the annealed samples, using transmission electron microscopy (TEM) and x-ray diffraction. GMR, as much as 80% at 5K and 25% at room temperature, have been observed. The absolute values of the resistivity (ρ) and the change of the resistivity (δρ) as functions of the magnetic Co concentration and the annealing temperature have been determined. A linear relation between δρ and I/rco, where rco is Co particle size, has been found. This result suggests that the magnetic scattering at the interfaces is crucial to GMR.

Study on Oxidation Resistance of Ti1-xAlxN Coating

2012 ◽  
Vol 534 ◽  
pp. 97-100
Author(s):  
C.L. Zhong ◽  
P.A. Wei ◽  
L.E. Luo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oxidation Resistance ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Compound Coating ◽  
Cubic Structure ◽  
Scanning Electron

A series of Ti1-xAlxN coatings were deposited by reactive magnetron sputtering. The content, microstructure and surface morphology of the coatings were characterized by energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of Al content on the microstructure and the oxidation resistance was studied. It was found that Ti1-xAlxN compound coating exhibits a cubic structure with (1 1 1) preferred orientations. The oxidation resistance obviously improves with the increase of Al content.

Analysis of the Solid Solution Microstructure of (HF) Al-Zn Alloys

2010 ◽  
Vol 303-304 ◽  
pp. 39-53 ◽  
Author(s):  
H. Bedboudi ◽  
A. Bourbia ◽  
M. Draissia ◽  
S. Boulkhessaim ◽  
M.Y. Debili
Keyword(s):  
High Frequency ◽  
Vickers Microhardness ◽  
Induction Melting ◽  
Strengthening Mechanisms ◽  
X Ray Diffraction ◽  
Microstructural Characteristics ◽  
X Ray ◽  
Microhardness Testing ◽  
Rapidly Solidified ◽  
Zn Alloys

Rapidly solidified Al-Zn alloys with Zn contents ranging up to 50 wt.% were made under vacuum, by high-frequency (HF) induction melting, from compacted mixture targets of Al and Zn of fine (99.99 % purity) elemental powders. The microstructural characteristics and strengthening mechanisms were investigated. The crystallographic microstructures were characterized by means of X-ray diffraction (XRD) analyses and optical microscopy observations as well as Vickers microhardness testing. Detailed overviews of alloying solubility of zinc in aluminium were given. Extensive solid solutions of CFC Al were found in the (HF) Al-Zn alloys, and a higher Vickers microhardnesses compared to that of pure (HF) aluminium.

Hrem Studies of Rapidly Solidified Ni-Fe-Al-B Shape Memory Alloys.

1991 ◽  
Vol 246 ◽  
Author(s):  
R. Pērez ◽  
J. A. Juārez-Islas ◽  
P. Johansson ◽  
M. Wallin ◽  
S. J. Savage
Keyword(s):  
Shape Memory ◽  
Martensite Transformation ◽  
Melt Spinning ◽  
Image Contrast ◽  
X Ray Diffraction ◽  
Recoverable Strain ◽  
X Ray ◽  
Atomic Structures ◽  
Wide Range ◽  
Rapidly Solidified

AbstractA series of (NixFeyAlz)0.9983B0.0017 (where x=58-60, y=13-15 and z=26-28, in at%) alloys have been rapidly solidified by - melt spinning. The ribbons have been characterized by HREM, DSC, X-ray diffraction and recoverable strain measurements. The as-cast alloys exhibit excellent bend ductility (in contrast to B2 type alloys conventionally cast) and a wide range of transformation temperatures: Ms=244-466 K, Mf=200-395K, As=236-427K and Af=262-526K. X-ray diffraction shows the presence of β (NiAl), β′ (NiAl), γ (Ni3Al), γ′ (Ni3A1), Ni and other phases such as Fe3Al, FeAl, FeNi and Al5Fe2. It is the β- β′ diffusionless transformation which is responsible for the shape memory effect. The results obtained by transmission electron microscopy (TEM) show two different types of crystalline grains. In one case, the grains have a high density of twins which are the fingerprints of the martensite transformation. However, other areas in the specimen show crystalline grains with very poor image contrast due to the transformation from β′ -β. There are also sections in the specimens with domains of both crystalline sgrains in coexistance. Both crystalline grains have large amounts of precipitates. In the β′ (NiAl) phase the size of the precipitates range fron lnm to lOnm. In the γ (Ni3Al) phase large precipitates (20nm) can be found. Some of them display pentagonal shapes which resemble the image contrast obtained in the TEM for small icosahedral metallic particles. Experimental evidence is also obtained on different habit or twin planes. HREM images from the twinned areas suggest diferent kinds of atomic structures for the parent and martensite crystalline sections. These results give some insights into the nature of the martensite transformation.

Heat Treatment of Nanocrystalline Al2O3-Zr02

1996 ◽  
Vol 457 ◽  
Author(s):  
Bridget M. Smyser ◽  
Jane F. Connelly ◽  
Richard D. Sisson ◽  
Virgil Provenzano
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Grain Size ◽  
Monoclinic Phase ◽  
Phase Distribution ◽  
Critical Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated

ABSTRACTThe effects of grain size on the phase transformations in nanocrystalline ZrO2-Al2O3 have been experimentally investigated. Compositions from 10 to 50 vol% Al2O3 in ZrO2 were obtained as a hydroxide gel. The powders were then calcined at 600 °C for 17 hours and heat treated at 1100 °C for 24 and 120 hours and at 1200 °C for 2 hours. The phase distribution and grain size were determined using x-ray diffraction and transmission electron microscopy. The initial grain size after calcining was 8–17 nm. It was determined that the critical ZrO2 grain size to avoid the tetragonal to monoclinic phase transformation on cooling from 1100 °C was between 17 and 25 nm. Samples containing 50% Al2O3 maintained a grain size below the critical size for all times and temperatures. The 30% Al2O3 samples showed the same behavior in all but one heat treatment. The remainder of the samples showed significant grain growth and at least partial transformation to the monoclinic phase.

Structures and phase transitions of B-Ta2O5 and Z-Ta2O5: two high-pressure forms of Ta2O5

2000 ◽  
Vol 56 (4) ◽  
pp. 659-665 ◽  
Author(s):  
I. P. Zibrov ◽  
V. P. Filonenko ◽  
M. Sundberg ◽  
P.-E. Werner
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
Rietveld Method ◽  
High Pressure Chamber ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated

A sample of Ta2O5, ditantalum pentaoxide, heat-treated in a `toroid'-type high-pressure chamber at P = 8 GPa and T = 1470 K, was studied by X-ray powder diffraction and high-resolution transmission electron microscopy (HRTEM). Two high-pressure modifications of Ta2O5, isostructural with B-Nb2O5 and Z-Nb2O5, were identified from the X-ray powder pattern. Both structures were refined by the Rietveld method from the X-ray diffraction data: B-Ta2O5, a = 12.7853 (4), b = 4.8537 (1), c = 5.5276 (2) Å, β = 104.264 (2)°, V = 332.45 Å3, Z = 4, space group C2/c; Z-Ta2O5, a = 5.2252 (1), b = 4.6991 (1), c = 5.8534 (1) Å, β = 108.200 (2)°, V = 136.53 Å3, Z = 2, space group C2. The Z-Ta2O5 modification is new. The Ta atoms are six-coordinated in B-Ta2O5 and seven-coordinated in Z-Ta2O5. The two structures are closely related, which makes an intergrowth and a transformation between them possible. An idealized model of the intergrowth structure has been given. The HRTEM study showed defect-rich B-Ta2O5 crystals, which could be interpreted as an intergrowth between the B-Ta2O5 and Z-Ta2O5 phases.

Rapid Solidification Microstructures and Precipitation in AL-Mn Alloys

1983 ◽  
Vol 28 ◽  
Author(s):  
R. J. Schaefer ◽  
D. Shechtman ◽  
F. S. Biancaniello
Keyword(s):  
Rapid Solidification ◽  
Growth Kinetics ◽  
Melt Spinning ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapidly Solidified ◽  
Solidification Microstructures ◽  
Al Matrix

ABSTRACTRapidly solidified Al containing up to to 15 wt.% Mn was prepared by melt spinning. The alloys were examined by TEM and X-ray diffraction in the as-spun condition and after annealing at 450°C. Four precipitate phases were detected, and their growth kinetics were correlated to subgrain structures in the Al matrix.

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