scholarly journals Plastic straining and concomitant microstructure recrystallization of Ni-Cu alloy in the undercooled condition

2022 ◽  
Vol 1217 (1) ◽  
pp. 012005
Author(s):  
H An ◽  
N J Siambun ◽  
B L Chua ◽  
M J H Gan
Keyword(s):  
Rapid Solidification ◽  
Solidification Structure ◽  
Dislocation Network ◽  
Comparative Experiment ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Equilibrium Solidification ◽  
Strong Deformation ◽  
Rapidly Solidified ◽  
Microstructure And Microtexture

Abstract Microstructure and microtexture of rapidly solidified undercooled Ni-Cu alloys were investigated. The characteristic undercooling of Ni80Cu20 alloy was determined as 45K, 90K and 160K. Dendrite deformation due to rapid solidification led to strong deformation microtexture. Due to recrystallization upon annealing after recalescence, many subgrains were formed in the microstructure. Further, annealing the quenched alloy at 900°, new microtextures and subgrains were formed, which was due to recrystallization and dislocation network rearrangement. The results of comparative experiment proved the recrystallization mechanism of the microstructure refinement in the non-equilibrium solidification structure of the undercooled binary alloy

Microstructure and Properties of Rapidly Solidified Al-Zn-Mg-Cu Alloy

2020 ◽  
Vol 993 ◽  
pp. 203-207
Author(s):  
Wei Min Ren ◽  
Zi Yong Chen ◽  
Zhi Lei Xiang ◽  
Li Hua Chai
Keyword(s):  
Aluminum Alloy ◽  
Aluminum Alloys ◽  
Cooling Rate ◽  
Rapid Solidification ◽  
Second Phase ◽  
Alloy Strip ◽  
Roller Speed ◽  
Microstructure And Properties ◽  
Cu Alloy ◽  
Rapidly Solidified

Refining grain plays an important role in improving the mechanical properties of aluminum alloys. However, the conventional casting method with a slow cooling rate can be easy to cause coarseness of the microstructure and serious segregation. In this paper, the rapid solidification of Al-Zn-Mg-Cu alloy was prepared by the single-roller belt method. The alloy strip was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and hardness test to study the microstructure and properties of the rapidly solidified aluminum alloy. The results show that the roller speed was an important parameters affecting the formability of the alloy. When the roller speed was 15 m/s, the aluminum alloy produced a thin bandwidth of 5 mm and a thickness of 150 um. As the rotation speed of the roller increased, the cooling rate of the melt increased, and the microstructure of the rapidly solidified Al-Zn-Mg-Cu aluminum alloy strip improved in grains refinement. Compared with the conventionally cast Al-Zn-Mg-Cu aluminum alloys, the Al-Zn-Mg-Cu aluminum alloys prepared by rapid solidification showed much finer crystal grains, and enhanced solid solubility of alloying elements with less precipitation of second phase and high hardness.

Microstructure of Rapidly Solidified Melt-Spun Ribbon in AlCoCrFeNi2.1 Eutectic High-Entropy Alloys

2016 ◽  
Vol 879 ◽  
pp. 1350-1354 ◽  
Author(s):  
Takeshi Nagase ◽  
Mamoru Takemura ◽  
Mitsuaki Matsumuro
Keyword(s):  
Grain Boundary ◽  
Rapid Solidification ◽  
Crystalline Structure ◽  
Xrd Analysis ◽  
Solidification Structure ◽  
High Entropy Alloys ◽  
High Entropy ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Rapidly Solidified

The microstructure of rapidly solidified melt-spun ribbon in AlCoCrFeNi2.1 eutectic high entropy alloys (EHEAs) was investigated for clarifying the effect of rapid solidification on the constituent phases and microstructure of specimens formed through solidification. XRD analysis indicates that the melt-spun ribbons were composed of a mixture of fcc and bcc phases. The rapidly solidified melt-spun ribbon shows a fine poly-crystalline structure with fcc matrix phase and crystalline precipitates in the grain boundary, indicating that the solidification structure in the melt-spun ribbon was significantly different from that obtained by conventional casting processes.

Investigation of Square Wave Pulsed Currents on Solidification Behavior of Al-Cu Alloys

2010 ◽  
Vol 160-162 ◽  
pp. 1767-1771
Author(s):  
Xiao Tian Yang ◽  
Xia Li ◽  
Wen Sheng Li
Keyword(s):  
Temperature Region ◽  
Solidification Process ◽  
Solidification Structure ◽  
Recording Instrument ◽  
Metal Solidification ◽  
Square Wave ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Temperature Recording ◽  
Equiaxed Grains

Al-(4-5)%Cu alloy was served as experiment material，the effect of pulsed currents on the solidification structure was investigated. During the solidification process of Al-Cu alloys, pulsed currents was added into the melted alloy in the crucible .The change of temperature curve and microstructure about the alloy was investigated in such conditions by temperature-recording instrument and optical microscope.The results showed that pulsed currents can shorten the temperature region of crystallization and refine the grains of the alloy,which crush the dendrite and make the solidification structure non-dendrite, presenting columnar and equiaxed grains which are distributed evenly and whose space between crystals are reduced. This investigation firstly started to study the relations between the temperature region of crystallization and organization structure of solidification. Finally, the mechanism of metal solidification affected by square wave pulsed currents was discussed.

Analysis of a Rapidly Solidified High-Phosphorus Austenitic Steel Containing an Amorphous Phase

1981 ◽  
Vol 8 ◽  
Author(s):  
T. F. Kelly ◽  
G. B. Olson ◽  
J. B. Vander Sande
Keyword(s):  
Austenitic Steel ◽  
Rapid Solidification ◽  
Amorphous Phase ◽  
Cell Walls ◽  
Solidification Structure ◽  
Metastable Austenite ◽  
Glass Forming ◽  
High Phosphorus ◽  
Rapidly Solidified

ABSTRACTRapid solidification of a high-phosphorus austenitic steel produces a fine cellular solidification structure containing an amorphous phase at the cell walls. The amorphous phase, which is stable to ∼500°C, is enriched in phosphorus and chromium, but contains significantly less phosphorus than conventional glass-forming alloys. Hot consolidation of powders produces a chemically-uniform metastable austenite which can be effectively precipitation hardened by phospho-carbides.

Grain refinement mechanism of rapidly solidified nickel alloys

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hongfu Wang ◽  
Hongen An ◽  
Shaopei Yang
Keyword(s):  
Grain Refinement ◽  
Nickel Alloys ◽  
Boundary Migration ◽  
Solidification Structure ◽  
Grain Boundary Migration ◽  
High Undercooling ◽  
Cu Alloys ◽  
Refinement Mechanism ◽  
Rapidly Solidified ◽  
Equiaxed Grains

Abstract The solidification microstructure evolution of Ni-25 at.% Cu alloys under different undercooling degrees were studied by the cladding method and cyclic superheating method. Two grain refinement phenomena were observed in the obtained undercooling. In the low undercooling condition, dendrite remelting is the main reason for grain refinement in the recalescence process, while in the high undercooling condition, the stress accumulated in the recalescence process leads to recrystallization in the later stage of recalescence. Under the condition of high undercooling, the solidification structure is composed of complete equiaxed grains with relatively uniform grain size, which indicates that grain boundary migration occurs during grain growth.

Microstructure of Rapidly Solidified Nb3Al-X Ribbons

1990 ◽  
Vol 213 ◽  
Author(s):  
Ken Yasuda ◽  
Tetsuo Fujiwara ◽  
Hideyo Kodama ◽  
Masateru Suwa
Keyword(s):  
High Temperature ◽  
Rapid Solidification ◽  
Ternary Alloys ◽  
Solidification Structure ◽  
High Temperature Material ◽  
Melt Spin ◽  
Rapidly Solidified ◽  
Niobium Aluminide ◽  
The Relationship

ABSTRACTNb-Al and Nb-Al-X(X is Cr,Ti or Zr) ternary alloys ribbons, with compositions around the A15 (Nb3Al) structure, a candidate intermetallic as an advanced high temperature material, were rapidly solidified by an arc melt spin process. The rapid solidification structure of these tri-niobium aluminide alloys and the relationship between formed phases and compositions of ribbons are investigated.

Plastic deformation of θ ' in Al-4%Cu alloy

1978 ◽  
Vol 36 (1) ◽  
pp. 576-577
Author(s):  
Shrikant P. Bhat
Keyword(s):  
Deformation Behavior ◽  
Room Temperature ◽  
Electron Microscopic Observation ◽  
Bulk Alloy ◽  
Electron Microscopic ◽  
Cu Alloy ◽  
Cu Alloys ◽  
Orowan Mechanism ◽  
The Subject ◽  
Cyclic Straining

deformation behavior of Al-Cu alloys aged to contain θ ' has been the subject of many investigations (e.g., Ref. 1-5). Since θ ' is strong and hard, dislocations bypass θ ' plates (Orowan mechanism) at low strains. However, at high strains the partially coherent θ ' plates are probably sheared, although the mechanism is complex, depending on the form of deformation. Particularly, the cyclic straining of the bulk alloy is known to produce gross bends and twists of θ '. However, no detailed investigation of the deformation of θ ' has yet been reported; moreover, Calabrese and Laird interpreted the deformation of θ ' as largely being elastic.During an investigation of high temperature cyclic deformation, the detailed electron-microscopic observation revealed that, under reversed straining conditions, θ ' particles are severely distorted--bent and twisted depending on the local matrix constraint. A typical electronmicrograph, showing the twist is shown in Fig. 1. In order to establish whether the deformation is elastic or plastic, a sample from a specimen cycled at room temperature was heated inside the microscope and the results are presented in a series of micrographs (Fig. 2a-e).

Lorentz electron microscopy of magnetic domains in rapidly solidified and annealed Pt-Co-B alloys

1991 ◽  
Vol 49 ◽  
pp. 784-785
Author(s):  
N. Qiu ◽  
J. E. Wittig
Keyword(s):  
Rapid Solidification ◽  
Ion Beam ◽  
Magnetic Behavior ◽  
High Coercivity ◽  
Magnetic Domains ◽  
Beam Angle ◽  
Tem Analysis ◽  
Intrinsic Coercivity ◽  
Hard Magnets ◽  
Rapidly Solidified

PtCo hard magnets have specialized applications owing to their relatively high coercivity combined with corrosion resistance and ductility. Increased intrinsic coercivity has been recently obtained by rapid solidification processing of PtCo alloys containing boron. After rapid solidification by double anvil splat quenching and subsequent annealing for 30 minutes at 650°C, an alloy with composition Pt42Co45B13 (at.%) exhibited intrinsic coercivity up to 14kOe. This represents a significant improvement compared to the average coercivities in conventional binary PtCo alloys of 5 to 8 kOe.Rapidly solidified specimens of Pt42Co45B13 (at.%) were annealed at 650°C and 800°C for 30 minutes. The magnetic behavior was characterized by measuring the coercive force (Hc). Samples for TEM analysis were mechanically thinned to 100 μm, dimpled to about 30 nm, and ion milled to electron transparency in a Gatan Duomill at 5 kV and 1 mA gun current. The incident ion beam angle was set at 15° and the samples were liquid nitrogen cooled during milling. These samples were analyzed with a Philips CM20T TEM/STEM operated at 200 kV.

Transmission Electron Microscopic Observations of Al3Li and Al3Ti Precipitation in A Rapidly Solidified Al-3Li-0.2Ti ALLOY

1980 ◽  
Vol 38 ◽  
pp. 336-337
Author(s):  
J. E. O’Neal ◽  
K. K. Sankaran ◽  
S. M. L. Sastry
Keyword(s):  
Rapid Solidification ◽  
Metallic Substrate ◽  
Deformation Characteristics ◽  
Phase Decomposition ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Supersaturated Solid Solutions ◽  
Transmission Electron Microscopic ◽  
Rapidly Solidified ◽  
Microstructural Homogeneity

Rapid solidification of a molten, multicomponent alloy against a metallic substrate promotes greater microstructural homogeneity and greater solid solubility of alloying elements than can be achieved by slower-cooling casting methods. The supersaturated solid solutions produced by rapid solidification can be subsequently annealed to precipitate, by controlled phase decomposition, uniform 10-100 nm precipitates or dispersoids. TEM studies were made of the precipitation of metastable Al3Li(δ’) and equilibrium AL3H phases and the deformation characteristics of a rapidly solidified Al-3Li-0.2Ti alloy.

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.

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