Cooling Rate and Microstructural Investigation of Rapidly Solidified Spherical Mono-Sized Copper Particles

2020 ◽  
Vol 976 ◽  
pp. 42-49
Author(s):  
Ying Yan Hu ◽  
Jun Feng Wang ◽  
Can Li ◽  
Yi Ying Gao ◽  
Jian Qiang Li
Keyword(s):  
Grain Boundary ◽  
Cooling Rate ◽  
Rapid Solidification ◽  
Particle Diameter ◽  
Spherical Shape ◽  
Microstructural Investigation ◽  
Argon Gas ◽  
Copper Particles ◽  
Rapidly Solidified ◽  
The Relationship

Spherical copper particles with diameter ranging from 120.6 to 437.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). These spherical copper particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid copper can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the relationship between cooling rate and microstructures of spherical copper particles was carried out with a specific focus on different cooling atmosphere and particle diameter during the rapid solidification. The cooling rate of spherical copper particles is evaluated by a Newton’s cooling model. It is revealed that the cooling rate was depended on cooling medium and particle diameter. The cooling rate decreases and the grain size increases with the increase of particle diameter during the rapid solidification, while the grain boundary of same particle diameter with larger cooling rate in argon gas is smaller, while the grain boundary of particles with smaller cooling rate in helium gas is larger. When the particle diameter is larger than 100 μm, the cooling rate of the cooper droplet in argon gas achieves 1.0×104 K/s. Meanwhile, the cooling rate decreases rapidly when the particle diameter increased between 70.6 and 149.6 μm. It is an effective route for fabrication of high-quality spherical copper particles.

Characterization of Cooling Rate and Microstructure of Rapidly Solidified Spherical Mono-Sized Sn-1.0Ag-0.5Cu Particles

2019 ◽  
Vol 960 ◽  
pp. 274-283
Author(s):  
Ying Yan Hu ◽  
Jun Feng Wang ◽  
Can Li ◽  
Jian Qiang Li
Keyword(s):  
Particle Size ◽  
Cooling Rate ◽  
Rapid Solidification ◽  
Great Influence ◽  
Particle Diameter ◽  
Spherical Shape ◽  
Phase Size ◽  
Rapidly Solidified ◽  
The Relationship

Spherical mono-sized Sn-1.0Ag-0.5Cu (wt.%) particles with diameter ranging from 124.0 to 337.4μm were prepared by the pulsated orifice ejection method (termed “POEM”).These spherical Sn-1.0Ag-0.5Cu particles exhibit a good spherical shape and a narrow size distribution, suggesting that liquid Sn-1.0Ag-0.5Cu can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the relationship between cooling rate and microstructures of spherical Sn-1.0Ag-0.5Cu particles was studied with a specific focus on different particle diameter during the rapid solidification. The cooling rate of spherical Sn-1.0Ag-0.5Cu particles with different diameter was evaluated by the Newton’s cooling model. It is revealed that the cooling rate decreases gradually with the increase of particle size during the rapidly solidified process. When the particle diameter is equal to 75 μm, the cooling rate of the Sn-1.0Ag-0.5Cu particle achieves 4.30×103 K/s which indicates that smaller particles can rapidly solidified due to their higher cooling rate. Meanwhile, the cooling rate decreases rapidly when the particle diameter increases between 75 and 100 μm. Furthermore, the different particle diameter with different cooling rate has a great influence on the solidification microstructure of Sn-1.0Ag-0.5Cu particles. The cooling rate and grain boundary size decreases with the increase of particle diameter during the rapid solidification. In addition, the phase size of βSn increases with the decrease of particle size. Smaller particles have relatively high cooling rate and it gives less solidification time as compared to larger particles. It is an effective route for fabrication of high-quality spherical Sn-1.0Ag-0.5Cu particles. Keywords: Spherical Sn-1.0Ag-0.5Cu particles; Rapid solidification; Structural; Cooling rate

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.

scholarly journals The Effect of Cooling Rate During Rapid Solidification on the Structure and Texture of NiTi

1986 ◽  
Vol 74 ◽  
Author(s):  
A. J. Pedraza ◽  
M. J. Godbole ◽  
E. A. Kenik ◽  
D. F. Pedraza ◽  
D. H. Lowndes
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Heat Extraction ◽  
X Ray Diffraction ◽  
Rapid Solidification Technique ◽  
Melted Layer ◽  
Monoclinic Distortion ◽  
Small Distortion ◽  
B2 Phase ◽  
Rapidly Solidified

AbstractA study has been conducted on the effects of increasing cooling rate during rapid solidification of NiTi upon the phases that are produced. The hammer and anvil rapid solidification technique and laser melting with a nanosecond excimer laser were used, which allow the cooling rate to be varied by three to four orders of magnitude. Although 1/3 {110} superlattice reflections are seen in the selected area diffraction (SAD) patterns of the splat quenched (SQ) specimens, x-ray diffraction analyses show the presence of only B2 phase and martensite. On the other hand, laser treatment (LT) of the specimens produces a layer that has a L10 structure with a slight monoclinic distortion. This phase can be envisaged as a small distortion of a B2 unit cell with a volume per atom ~3.3% lower than the equilibrium B2 phase. Also martensite is present in the layer. SQ alloys exhibit a marked {200} texture due to columnar growth opposite to the direction of heat extraction, while LT produces epitaxial regrowth of the melted layer. No substantial disordering is obtained in NiTi rapidly solidified alloys.

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.

Microstructure Evolution in Rapidly Solidified Immiscible Alloys

2006 ◽  
Vol 508 ◽  
pp. 37-44 ◽  
Author(s):  
Michael Reuß ◽  
Lorenz Ratke ◽  
Jiu Zhou Zhao
Keyword(s):  
Cooling Rate ◽  
Nucleation Rate ◽  
Particle Diameter ◽  
Casting Process ◽  
Average Particle ◽  
Cooling Rates ◽  
Gravity Casting ◽  
The Difference ◽  
Rapidly Solidified ◽  
Mould Casting

We prepared Al-Bi alloys with our new aerogel counter gravity casting facility and Al-Pb alloys by simple mould casting with variable cooling rates. By counter gravity casting, it is possible to have directional solidification with flat isotherms and without forced melt flow during the casting process. Both methods allow studying the nucleation rate in liquid-liquid decomposition. The most important result is that a separation between monotectic and hypermonotectic particles is possible by using suitable cooling rates. The difference of the frequency maxima is a function, depending on cooling rate and starting composition. By casting experiments with variable cooling rates, we found that the average particle diameter is a function of the cooling rate, according to the theory of Ratke and Zhao, but the nucleation rate is higher than assumed in their theory.

scholarly journals Nucleation behaviour and microstructure of single Al-Si12 powder particles rapidly solidified in a fast scanning calorimeter

2021 ◽  
Author(s):  
Bin Yang ◽  
Qin Peng ◽  
Benjamin Milkereit ◽  
Armin Springer ◽  
Dongmei Liu ◽  
...  
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Heterogeneous Nucleation ◽  
Cooling Rates ◽  
Solidification Behaviour ◽  
Nucleation Undercooling ◽  
In Situ Investigation ◽  
Solidification Processes ◽  
Powder Particles ◽  
Rapidly Solidified

AbstractThe understanding of rapid solidification behaviour, e.g. the undercooling versus growth velocity relationship, is crucial for tailoring microstructures and properties in metal alloys. In most rapid solidification processes, such as additive manufacturing (AM), in situ investigation of rapid solidification behaviour is missing because of the lack of accurate measurement of the cooling rate and nucleation undercooling. In the present study, rapid solidification of single micro-sized Al-Si12 (mass%) particles of various diameters has been investigated via differential fast scanning calorimetry employing controllable cooling rates from 100 to 90,000 K s−1 relevant for AM. Based on nucleation undercooling and on microstructure analysis of rapidly solidified single powder particles under controlled cooling rates, two different heterogeneous nucleation mechanisms of the primary α-Al phase are proposed. Surface heterogeneous nucleation dominates for particles with diameter smaller than 23 μm. For particles with diameter larger than 23 μm, the nucleation of the primary α-Al phase changes from surface to bulk heterogeneous nucleation with increasing cooling rate. The results indicate that at large undercoolings (> 95 K) and high cooling rates (> 10,000 K s−1), rapid solidification of single particle can yield a microstructure similar to that formed in AM. The present work not only proposes new insight into rapid solidification processes, but also provides a theoretical foundation for further understanding of microstructures and properties in additively manufactured materials.

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.

Mechanical Properties of Rapidly Solidified Ni3Ge and Ni5Ge3 Intermetallic Compounds

2020 ◽  
Vol 20 (7) ◽  
pp. 4591-4596
Author(s):  
Nafisul Haque ◽  
Oluwatoyin E. Jegede ◽  
Andrew M. Mullis
Keyword(s):  
Cooling Rate ◽  
Intermetallic Compounds ◽  
Vickers Hardness ◽  
Single Phase ◽  
Hardness Test ◽  
Growth Direction ◽  
Drop Tube ◽  
Microstructural Investigation ◽  
Phase Intermetallic ◽  
Rapidly Solidified

The congruently melting, single phase, intermetallic compounds β-Ni3Ge and ε-Ni5Ge3 were produced by arc melt. Each was subject to rapid solidification via drop-tube processing. Each compound remained fully single phase (either β-Ni3Ge or ε-Ni5Ge3) irrespective of the imposed cooling rate. In the investigation of β-Ni3Ge compound, droplets spanning the size range ≥850 to ≤38 μm diameter particles, with corresponding cooling rates of <700 to >54500 K s−1, were subject to microstructural investigation using SEM. Six dominant solidification morphologies were identified with increasing cooling rate, namely; (i) spherulites, (ii) mixed spherulites and dendrites, (iii) dendrites-orthogonal, (iv) dendrites-non-orthogonal, (v) recrystallized, and (vi) dendritic seaweed, are observed imbedded within a featureless matrix. For the ε-Ni5Ge3 compound, four dominant solidification morphologies were observed, namely; (i) partial plate and lath, (ii) plate and lath microstructure (iii) isolated hexagonal crystallites, and (iv) single crystal imbedded within a featureless matrix. Micro-Vickers hardness test result of both compounds showed a complex dependence of micro hardness upon cooling rate. At 700 K s−1 the hardness was significantly lower in both compounds than the reported equilibrium value, although in both cases this subsequently increased with further increases in cooling rate. Moreover, in both cases, microstructural transition, such as change in growth direction, led to abrupt drops in hardness. The micro-Vickers hardness results confirmed that the ε-Ni5Ge3 is significantly harder (maximum 1021 Hv0.01) than the β-Ni3Ge compound (maximum 526 Hv0.01).

Microstructures of Ni3 Al Rapidly Solidified by Hammer-Anvil Technique

1990 ◽  
Vol 186 ◽  
Author(s):  
Yoshinao Mishima ◽  
Shirou Sasaki ◽  
Tomoo Suzuki
Keyword(s):  
Cooling Rate ◽  
Rapid Solidification ◽  
Phase Field ◽  
Aluminum Concentration ◽  
The Difference ◽  
Equilibrium Phases ◽  
Rapidly Solidified ◽  
Non Equilibrium

AbstractThe Hammer-Anvil technique is employed for the rapid solidification of Ni3Al in the present work. The effect of off-stoichiometry on the change in the microstructure in the quenched alloy is examined for compositions within the L12 phase field at equilibrium. It is shown that non-equilibrium phases of various morphologies appear with fine grains of Ll2 phase, which have never been reported for the compound rapidly solidified by the roll techniques. With increasing aluminum concentration and with increase in cooling rate, the latter being judged by the difference in the thickness of the quenched foil, the fraction of the non-equilibrium phases appearing is found to increase giving more complex microstructure.

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