Rapidly Solidified Binary Tial Alloys

1986 ◽  
Vol 81 ◽  
Author(s):  
S. C. Huang ◽  
E. L. Hall ◽  
M. F. X. Gigliotti
Keyword(s):  
Electron Diffraction ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Grain Structure ◽  
Bending Tests ◽  
Tial Alloys ◽  
Compositional Effect ◽  
X Ray ◽  
Antiphase Domains ◽  
Rapidly Solidified

AbstractMelt spinning has been carried out on binary TiAl alloys at three Ti/Al ratios. Antiphase domains were observed in one ribbon specimen, but no significant disordering was induced by the rapid solidification as indicated by X-ray and electron diffraction analyses. Bending tests of both the ribbons and the consolidated counterparts showed a decrease in ductility with increasing Al concentration. This compositional effect can be correlated with the TiAl tetragonality (the c/a ratio) as well as the grain structure.

Substructure Development in Rapidly Solidified B2-Type TiCo Ribbons

2005 ◽  
Vol 475-479 ◽  
pp. 849-852 ◽  
Author(s):  
Kyosuke Yoshimi ◽  
Minseok Sung ◽  
Sadahiro Tsurekawa ◽  
Akira Yamauchi ◽  
Ryusuke Nakamura ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Dislocation Density ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Grain Structure ◽  
Second Phase ◽  
Rapidly Solidified ◽  
Equiaxed Grain

Substructure development through aging and annealing treatments was studied for rapidly solidified TiCo ribbons using TEM. In as-spun ribbons, equiaxed grain structure was developed and its crystal structure was B2-ordered immediately after melt-spinning, while a small amount of fine precipitates existed as second phase. Some grains were dislocation-free but others contained a certain amount of curved or helical dislocations and loops. The dislocation density in the ribbons annealed at 700 °C for 24 h was obviously higher than those in the as-spun ribbons and the ribbons aged at 200 °C for 100 h. The increase of the dislocation density in the annealed ribbons would result from the absorption of excess vacancies. Therefore, the obtained results indicated that a large amount of supersaturated thermal vacancies were retained in TiCo as-spun ribbons by the rapid solidification.

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.

Phase distribution in rapidly solidified TiAl alloys

1989 ◽  
Vol 47 ◽  
pp. 322-323
Author(s):  
Ernest L. Hall ◽  
Shyh-Chin Huang
Keyword(s):  
Rapid Solidification ◽  
Melt Spinning ◽  
Phase Distribution ◽  
Equilibrium Phase ◽  
Aircraft Engine ◽  
Equilibrium Phase Diagram ◽  
Tial Alloys ◽  
Face Centered ◽  
Rapidly Solidified ◽  
Microstructural Studies

There is at present a great deal of interest in the intermetallic compound γ-TiAl, particularly with regard to its use as an aircraft engine or aerospace structural material. This compound possesses an attractive combination of properties, including high melting temperature, low density, high modulus, and good oxidation and creep resistance, but is somewhat deficient in room temperature ductility due to its crystal structure, which is the Ll0 face-centered tetragonal structure consisting of alternating (002) planes of Ti and Al. The Ti-Al equilibrium phase diagram in the vicinity of γ-TiAl shows that γ-TiAl forms via a peritectic reaction and thus, in order to minimize segregation and to insure maximum homogeneity, it is desirable to produce γ-TiAl alloys by rapid solidification. It is then useful, in order to establish a baseline for advanced alloy design, to have an understanding of the microstructures resulting from rapid solidification. In this paper, we report the results of microstructural studies of binary Ti-Al alloys varying in stoichiometry from 46 to 70 at. % Al which were rapidly solidified into the form of ribbon using melt spinning.

Metastable ordered austenite in rapidly solidified Fe-Al-C alloys

1989 ◽  
Vol 47 ◽  
pp. 516-517
Author(s):  
J. A. Sarreal
Keyword(s):  
Rapid Solidification ◽  
Melt Spinning ◽  
X Ray Diffraction ◽  
Austenitic Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Equilibrium Phases ◽  
Rapidly Solidified

Conventionally cast Fe-Al-C alloys are extremely brittle containing combinations of ferrite, carbide and other phases. Rapid solidification has the potential of altering the microstructure to subsequently change the resulting mechanical properties. An apparent conflict exist concerning the effect of rapid solidification on the resulting microstructure of these alloys. Inoue and co-workers, using transmission electron microscopy (TEM) and electron diffraction analyses, reported the presence of several non-equilibrium phases including austenite (fcc - γ) and ordered austenite (Ll2-γ') structures on alloys containing 1.7 to 2.1 C and 6 to 12 Al in weight % (w/o) on melt spun ribbons 30 μm in thickness. Han and Choo, using x-ray diffraction analysis on 30-48 μm thick melt spun ribbons concluded that this ordered fee phase is rather an austenitic phase in which phase decomposition accompanied by sideband phenomenon had occured.Single roller melt spinning technique was used to make ribbons 35-70 μm thick and 0.5-5 mm wide. X-ray diffration analysis showed single phase austenite for samples 2-6 w/o AI and 2 w/o C. Samples with 8-10 w/o AI and 2 w/o C also showed several superlattice lines in addition to the fundamental fcc peaks.

New Fe-Ni Based Metal-Metalloid Glassy Alloys Prepared by Mechanical Alloying and Rapid Solidification

1996 ◽  
Vol 455 ◽  
Author(s):  
J. J. Suñol ◽  
M. T. Clavaguera-Mora ◽  
N. Clavaguera ◽  
T. Pradell
Keyword(s):  
Mechanical Alloying ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Magnetic Interaction ◽  
Processing Route ◽  
Mechanically Alloyed ◽  
Scanning Calorimetry ◽  
Glassy Alloys ◽  
Rapidly Solidified ◽  
Thermal Stability Of

ABSTRACTMechanical alloying and rapid solidification are two important routes to obtain glassy alloys. New Fe-Ni based metal-metalloid (P-Si) alloys prepared by these two different processing routes were studied by differential scanning calorimetry and transmission Mössbauer spectroscopy. Mechanical alloyed samples were prepared with elemental precursors, and different nominal compositions. Rapidly solidified alloys were obtained by melt-spinning. The structural analyses show that, independent of the composition, the materials obtained by mechanical alloying are not completely disordered whereas fully amorphous alloys were obtained by rapid solidification. Consequently, the thermal stability of mechanically alloyed samples is lower than that of the analogous material prepared by rapid solidification. The P/Si ratio controls the magnetic interaction of the glassy ribbons obtained by rapid solidification. The experimental results are discussed in terms of the degree of amorphization and crystallization versus processing route and P/Si ratio content.

scholarly journals The Production of Material with Ultrafine Grain Structure in Al-Zn Alloy in the Process of Rapid Solidification

2014 ◽  
Vol 14 (2) ◽  
pp. 57-62
Author(s):  
M. Szymaneka ◽  
B. Augustyn ◽  
D. Kapinos ◽  
S. Boczkal ◽  
J. Nowak
Keyword(s):  
Rapid Solidification ◽  
Melt Spinning ◽  
Hot Extrusion ◽  
High Strength ◽  
Strength Properties ◽  
Grain Structure ◽  
Ultrafine Grain ◽  
Plastic Working ◽  
Metal Treatment ◽  
Ultrafine Grain Structure

Abstract In the aluminium alloy family, Al-Zn materials with non-standard chemical composition containing Mg and Cu are a new group of alloys, mainly owing to their high strength properties. Proper choice of alloying elements, and of the method of molten metal treatment and casting enable further shaping of the properties. One of the modern methods to produce materials with submicron structure is a method of Rapid Solidification. The ribbon cast in a melt spinning device is an intermediate product for further plastic working. Using the technique of Rapid Solidification it is not possible to directly produce a solid structural material of the required shape and length. Therefore, the ribbon of an ultrafine grain or nanometric structure must be subjected to the operations of fragmentation, compaction, consolidation and hot extrusion. In this article the authors focussed their attention on the technological aspect of the above mentioned process and described successive stages of the fabrication of an AlZn9Mg2.5Cu1.8 alloy of ultrafine grain structure designated for further plastic working, which enables making extruded rods or elements shaped by the die forging technology. Studies described in the article were performed under variable parameters determined experimentally in the course of the alloy manufacturing process, including casting by RS and subsequent fragmentation.

Microstructure & Phase Transformation in Rapidly Solidified V-Ga Alloys

1986 ◽  
Vol 80 ◽  
Author(s):  
M. W. Park ◽  
S. H. Whang ◽  
S. Karmarkar ◽  
D. Divecha
Keyword(s):  
Heat Treatment ◽  
Phase Transformation ◽  
Grain Refinement ◽  
Rapid Solidification ◽  
Rapid Quenching ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rapidly Solidified ◽  
A15 Phase

AbstractThe A15 Phase forming V-Ga alloys were processed into ribbons and foils by rapid solidification techniques. Microstructures and phase transformation in these alloys by rapid solidification and succeeding heat treatment were investigated by x-ray diffraction and TEM. It is shown that equilibrium A15 phases can readily be suppressed by rapid quenching in these alloys. A significant grain refinement resulting from the rapid solidification also was observed. Microhardnesses of these alloys as a function of Ga concentration were determined.

Rapidly solidified Al–Cr alloys: Crystalline and quasicrystalline phases

1989 ◽  
Vol 4 (3) ◽  
pp. 539-551 ◽  
Author(s):  
V. T. Swamy ◽  
S. Ranganathan ◽  
K. Chattopadhyay
Keyword(s):  
Rapid Solidification ◽  
Sudden Change ◽  
Grain Structure ◽  
Quasicrystalline Phase ◽  
Diffuse Intensity ◽  
Transmission Electron ◽  
Icosahedral Quasicrystals ◽  
Cast Alloys ◽  
Diffraction Patterns ◽  
Rapidly Solidified

Rapidly solidified Al–Cr alloys up to 20 at. % Cr were studied to delineate the extent of crystalline and quasicrystalline phase formation in these alloys in comparison with as-cast alloys by using transmission electron microscopy and x-ray diffraction technique. The icosahedral quasicrystals are observed from 7 to 15 at. % Cr alloys, while equilibrium η–Al11Cr2 phase is completely absent. Both rapid solidification and subsequent thermal decomposition studies indicate that the main competing phase is θ–Al2Cr up to 15 at. % Cr. Beyond this composition ∊–Al4Cr is the dominant phase together with a small amount of γ4–Al7Cr3. We have shown that the electron diffraction patterns of Al–Cr quasicrystals are often associated with a diffuse intensity distribution, indicative of short-range order. The change in quasilattice constant with composition suggests the existence of structural vacancies. Further, a sudden change from coarse to ultrafine quasicrystalline grain structure in Al-7 at. % Cr alloy points to a change in nucleation mechanism from heterogeneous to homogeneous mode during the rapid solidification.

Rapidly Solidified Al-6Si-3Cu Alloy

2008 ◽  
Vol 570 ◽  
pp. 103-108 ◽  
Author(s):  
C. Triveño Rios ◽  
Claudemiro Bolfarini ◽  
Walter José Botta Filho ◽  
Claudio Shyinti Kiminami
Keyword(s):  
Rapid Solidification ◽  
X Ray Diffraction ◽  
Type Alloy ◽  
X Ray ◽  
Optical Scanning ◽  
Transmission Electron ◽  
Al2cu Phase ◽  
Solidification Processes ◽  
Dendritic Arm Spacing ◽  
Rapidly Solidified

Rapid solidification processes, RSP, are powerful tools to induce microstructural modifications, which may improve mechanical properties of alloys. In this paper the influence of rapid solidification on the formation of the undesirable brittle intermetallic compounds promoted by Si and Fe in Al-6Si-3Cu (A319-type) alloy have been investigated. The alloy have been casted using both conventional method and water-cooled wedge-copper mould. The microstructures have been evaluated by using a combination of X-ray diffraction, optical, scanning and transmission electron microscopy, and by Vickers microhardness. By increasing the cooling rate the length of the intermetallic β-Al5FeSi phase decreased, accompanying the same tendency of the secondary dendritic arm spacing. These results are accompanied by an increasing in hardness. Moreover, the formation and growth of the Al2Cu phase have been suppressed. These microstructural and hardness changes with the rapid solidification might be attributed to the increased solid solution content of the elements in the Al matrix.

Copper-Base Alloys Processed by Rapid Solidification and Ion Implantation

1985 ◽  
Vol 58 ◽  
Author(s):  
J.V. Wood ◽  
C.J. Elvidge ◽  
E. Johnson ◽  
A. Johansen ◽  
L. Sarholt-Kristensen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Martensitic Transformation ◽  
Ion Implantation ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Scanning Calorimetry ◽  
Copper Base ◽  
Similarities And Differences ◽  
Rapidly Solidified

ABSTRACTAlloys of Cu-Sn and Cu-B have been processed by both melt spinning and ion implantation. In some instances (eg Cu-Sn alloys) rapidly solidified ribbons have been subjected to further implantation. This paper describes the similarities and differences in structure of materials subjected to a dynamic and contained process. For example in Cu-B alloys (up to 2wt% Boron) extended solubility is found in implanted alloys which is not present to the same degree in rapidly solidified alloys of the same composition. Likewise the range and nature of the reversible martensitic transformation is different in both cases as examined by electron microscopy and differential scanning calorimetry.

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