scholarly journals Microstructural Characterization and Mechanical Properties of Rapidly Solidified Al-Si Systems by Chill Block Melt-Spinning Technique.

2020 ◽  
Vol 17 ◽  
pp. 79-91
Author(s):  
Amal Elsherif ◽  
Mustafa Kamal ◽  
Rizk Mostafa Shalaby
Keyword(s):  
Melt Spinning ◽  
Applied Load ◽  
Microstructural Characterization ◽  
Fine Grained ◽  
Chill Block ◽  
Rapidly Solidified ◽  
Hardness Values ◽  
Microstructural Examination ◽  
Solidification Technology ◽  
Rapid Solidification Technology

AlـSi alloys with compositions (0, 0.1, 0.5, 0.9 and 1.3 wt.% Si) were manufactured by chill block melt spinning method. The resulting ribbons samples have been characterized by xـray diffraction (XRD) and scanning electron microscope (SEM). Detailed analysis of (XRD) shows that presence of f.c.c Al solid solution and Si particles embedded within the aluminum grains. Microstructural examination resulted that microstructure of the melt spun ribbons are more fine and uniformly distributed. Rapid solidification technology led to increase the solubility of Si in αـAl as confirmed by XRD. Micro hardness measurements were also carried out by Vickers microـhardness tester at applied load 25gm forced and different dwell time. It is concluded that the Vickers hardness values are sensitive to applied load and indentation time. It is also found that the highest values of Hv is sensitive to presence of Si as columnar shape with fine grained of Al by high cooling rate.

Microstructure of Nb3 (AlSiB) superconducting tapes with extremely high critical current densities

1989 ◽  
Vol 4 (3) ◽  
pp. 526-529 ◽  
Author(s):  
Mireille Treuil Clapp ◽  
Zhang Jian ◽  
Tariq Manzur
Keyword(s):  
Critical Current ◽  
Melt Spinning ◽  
Quenching Rate ◽  
Fine Grained ◽  
Annealing Conditions ◽  
Second Phases ◽  
Current Densities ◽  
Rapidly Solidified ◽  
Equiaxed Grains ◽  
A15 Phase

Alloys of Nb73Al12Si14.5B0.5 were rapidly solidified into amorphous ribbons using the melt spinning technique. These were isothermally annealed at temperatures ranging from 660 to 780 °C. The A15 phase began to crystallize at 700 °C and small amounts of second phases appeared at the higher temperatures. Crystallization was dependent on quenching rate as well as annealing conditions. Below 750 °C nucleation was nonuniform and was enhanced by surfaces and quenched-in nuclei. Above 750 °C nucleation became more uniform and completely crystalline ribbons with equiaxed grains ∼30 nm in diameter were obtained. These ultra fine grained ribbons had extremely high superconducting critical current densities of 8 × 1010 A/m2 and 5 × 1010 A/m2 at magnetic fields of 0.5 and 15 tesla, respectively, at 4.2 K.

Consolidation of Nickel Base Superalloys Powder by Low Pressure Plasma Deposition

1983 ◽  
Vol 30 ◽  
Author(s):  
R.W. Smith ◽  
L.G. Peterson ◽  
W.F. Schilling
Keyword(s):  
High Performance ◽  
Plasma Deposition ◽  
Titanium Aluminum ◽  
Turbine Disks ◽  
The Subject ◽  
Commercial Applications ◽  
Nickel Base ◽  
Rapidly Solidified ◽  
Solidification Technology ◽  
Rapid Solidification Technology

Powder Metallurgy (P/M) technology has seen an important series of advances in the past twenty-five or so years. It has progressed from a press + sinter methodology (which still has important uses) to one of being a complete processing technology where, ultimately, the structure and properties of totally new materials can be synthesized. A key step in this evolution was the application of P/M techniques to high performance materials such as nickel-based superalloys. This effort began in the early 1960's and has resulted in several important commercial applications such as P/M gas turbine disks and shafts.Attention has now turned to the potential use of Rapid Solidification Technology (RST) as a means of furthering the span of materials which can be made available for a wide variety of engineering applications. Rapidly solidified nickel, cobalt, titanium, aluminum and copper based materials are all the subject of extensive research and development at the present time (1).

Microstructural Characterization of Rapidly Solidified Carbide-Containing Ni-Base Superalloys

1985 ◽  
Vol 43 ◽  
pp. 48-49
Author(s):  
E. L. Hall ◽  
M. R. Jackson
Keyword(s):  
Melt Spinning ◽  
Base Alloy ◽  
Eutectic Reaction ◽  
Microstructural Characterization ◽  
Weight Percent ◽  
Primary Carbide ◽  
Temperature Capability ◽  
Nickel Base ◽  
Rapidly Solidified

The temperature capability of nickel-base superalloys which are used in aircraft turbines may be able to be extended if novel microstructures can be produced in these materials by rapid solidification. The primary goal of these efforts is to achieve a fine dispersion of small precipitates which are stable at high temperature in the alloys. One class of alloys which seem particularly promising are the eutectic superalloys, which solidify via a eutectic reaction in which a γ- γ’ matrix containing MC carbides is formed. For this investigation, alloys which contained either Ta, Ti, or V as the primary carbide former were studied. In all cases, the base alloy consisted of Ni-4%Co-4%Cr-5.5%Al-2%Mo-3%W-1.5%Re-0.3%C in weight percent. The alloys additionally contained either 9% Ta, 5.5% Ti, or 4.5% V (subsequently referred to as alloys A, B, and C, respectively). The alloys were rapidly solidified by melt-spinning in vacuum.

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.

Influence of W additions in rapidly solidified nial

1987 ◽  
Vol 45 ◽  
pp. 212-213
Author(s):  
I. E. Locci ◽  
M. V. Nathal
Keyword(s):  
Low Temperature ◽  
Melt Spinning ◽  
Matrix Composition ◽  
X Ray ◽  
Fine Grained ◽  
Free Jet ◽  
High Temperature Structural Material ◽  
Low Temperature Toughness ◽  
Pure Metals ◽  
Rapidly Solidified

The B2 aluminide NiAl has potential as a high temperature structural material, although its lack of low temperature toughness is a major obstacle. One strategy for improving low temperature toughness is by grain refinement. Fortunately, fine grained intermetallics appear to retain their strengths to much higher fractions of their melting point than do pure metals and alloys. The purpose of this study was to investigate the effects of melt spinning and small W additions on the grain size and stability of NiAl.Two alloys of the same matrix composition, equiatomic NiAl, were examined. One also contained 0.5 W at% (NiAl+W). The alloys were cast as ribbon ∼45 pm thick by ∼2.5 mm wide using a free jet melt spinning apparatus. To simulate consolidation conditions, sections of ribbon were annealed for 1 hour at either 1273 or 1573 °K in purified argon. Optical, X-ray and electron analyses of the as-spun and annealed ribbons were performed.

Formation of bulk β–FeSi2by annealing rapidly solidified α–FeSi2ribbons

2000 ◽  
Vol 15 (5) ◽  
pp. 1045-1047 ◽  
Author(s):  
Zhenhua Zhou ◽  
Jianhua Zhao ◽  
Wenkui Wang ◽  
Liling Sun
Keyword(s):  
Rapid Solidification ◽  
Phase Evolution ◽  
Subsequent Annealing ◽  
Electric Resistance ◽  
Simple Method ◽  
Higher Temperature ◽  
Rapidly Solidified ◽  
Solidification Technology ◽  
Rapid Solidification Technology

Solidification of FeSi2alloy by single-roller rapid solidification technology was studied, and monophase α–FeSi2ribbons were obtained. Phase evolution of the monophase and metastable α–FeSi2ribbons during subsequent annealing was studied within situelectric resistance measurements. The results show that the metastable α–FeSi2phase transforms into the β–FeSi2phase at about 620 °C and then transforms into the α–FeSi2phase again at a higher temperature when heated. A new relatively simple method to prepare bulk β–FeSi2alloy, that is, formation of bulk β–FeSi2alloy by annealing monophase α–FeSi2alloy, is presented.

Effect of Heat Treatment on Microstructure and Mechanical Property of 45XD and 47XD TiAl Alloys

2005 ◽  
Vol 475-479 ◽  
pp. 581-584 ◽  
Author(s):  
H. Zhu ◽  
Dong Yi Seo ◽  
Kouichi Maruyama
Keyword(s):  
Heat Treatment ◽  
Mechanical Property ◽  
Lamellar Structure ◽  
Tial Alloys ◽  
Fine Grained ◽  
Break Up ◽  
Fully Lamellar ◽  
Hardness Values ◽  
Microstructure And Mechanical Property ◽  
Microstructural Examination

The effect of heat treatment on microstructure and property of Ti-45 and 47Al-2Nb-2Mn+0.8%vol.%TiB2 alloys (45XD and 47XD) has been studied. Annealing and subsequent oil quench produced fine-grained fully lamellar structure (FGFL) in both alloys. For microstructural stabilization, the FGFL structures were subjected to different aging treatments. Microstructural examination showed that degradation of the FGFL structure, such as coarsening of γ lamellae, recrystallization of γ grains and break-up of a2 lamellae, presented to varying degrees after different aging treatments. Hardness values in the aged alloys decreased due to the degradation. The creep resistances were improved in the aged alloys though the degradation occurred, indicating that the aging treatments stabilized the FGFL structures effectively. The differences in the changes of properties caused by different aging treatments and compositions were compared in combination with the microstructural variants.

Microstructures of Rapidly Solidified Titanium-Eutectoid Former Alloys

1983 ◽  
Vol 28 ◽  
Author(s):  
S. Krishnamurthy ◽  
R. G. Vogt ◽  
D. Eylon ◽  
F. H. Froes
Keyword(s):  
Optical Microscopy ◽  
Rapid Solidification ◽  
Melt Spinning ◽  
Binary Alloys ◽  
Microstructural Characterization ◽  
Pendant Drop ◽  
Melt Extraction ◽  
Sem And Tem ◽  
Rapidly Solidified

ABSTRACTTitanium-base binary alloys containing eutectoid forming additions such as Fe, Si, W, and Cr were rapidly solidified by pendant drop melt extraction, melt spinning, and “hammer and anvil” techniques. The materials obtained were fibers, ribbons, and splats, respectively. The microstructures of these rapidly solidified materials were analyzed by optical microscopy, SEM, and TEM. The fibers showed fine microstructures near the quenched side, but less homogeneous and coarser microstructures were observed away from this side. Similar variations were observed between the edge and the center of splats. The results of this microstructural characterization are discussed, and a comparison made between microstructures obtained by the different rapid solidification methods used.

The Influence of Si Content on the Microstructure of Rapidly Solidified AlMnSi Foil

2011 ◽  
Vol 295-297 ◽  
pp. 307-310
Author(s):  
Yan Li ◽  
Chuan Xin Zhai ◽  
Chun Hua Xu
Keyword(s):  
Phase Transformation ◽  
Heat Stability ◽  
Phase Transformation Temperature ◽  
Transmission Electron ◽  
Microstructure Morphology ◽  
Si Content ◽  
Rapidly Solidified ◽  
Si Addition ◽  
Solidification Technology ◽  
Rapid Solidification Technology

The AlMn and AlMnSi foils were fabricated by rapid solidification technology. The microstructures of the foils with various Si content were studied by transmission electron microscope (TEM). The phases of the foils were indentified by X-ray diffractometer (XRD); the phase transformation temperatures of the foils measured by differential scanning calorimeter (DSC). The results showed that addition of Si in the AlMn foil can improve the heat stability (phase transformation temperature) from 543K to over 873K. The addition of Si can change the phase structure of the foils. The phases of AlMn foil conclude Al and Al6Mn while the phases of AlMnSi foils with 3% Si or 5% Si addition become Al and Al4.01MnSi0.74. The addition of Si can also change the microstructure morphology of the foils from the rod, block and petal-like to the homogeneous globular. With the increase in Si content, the grain sizes of the foils were refined.

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