Competitive Phase Selection in Fe-Ni Alloy Droplets

1995 ◽  
Vol 398 ◽  
Author(s):  
F. Gärtner ◽  
A. F. Norman ◽  
H. Assadi ◽  
A. L. Greer
Keyword(s):  
Free Energy ◽  
Interfacial Energy ◽  
Kinetic Modelling ◽  
Primary Phase ◽  
Drop Tube ◽  
Phase Selection ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Bcc Phase ◽  
Selection Of

ABSTRACTIn the solidification of Fe-Ni droplets (≤ 30 at.% Ni), the selection of different microstructures is dominated by the competition between the bcc and ccp phases. In drop-tube experiments ccp is the primary phase in some dilute (up to 7at% Ni) alloys although the bcc phase is favoured by a lower free energy and by a lower interfacial energy with the liquid. Competitive dendrite growth is a possible explanation for the formation of primary ccp. Comprehensive thermodynamic (CALPHAD) and kinetic modelling is undertaken to understand the growth competition. The origin of the observed primary phases is discussed.

scholarly journals Study on the Phase Selection and Debye Temperature of Hyper-Peritectic Al-Ni Alloy under High Pressure

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 84
Author(s):  
Xiaohong Wang ◽  
Zhipeng Chen ◽  
Duo Dong ◽  
Dongdong Zhu ◽  
Hongwei Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Competitive Growth ◽  
Phase Selection ◽  
Debye Temperatures ◽  
Ni Alloy ◽  
Temperature Heat ◽  
Low Temperature Heat Capacity ◽  
New Phase ◽  
Selection Of

The phase selection of hyper-peritectic Al-47wt.%Ni alloy solidified under different pressures was investigated. The results show that Al3Ni2 and Al3Ni phases coexist at ambient pressure, while another new phase α-Al exists simultaneously when solidified at high pressure. Based on the competitive growth theory of dendrite, a kinetic stabilization of metastable peritectic phases with respect to stable ones is predicted for different solidification pressures. It demonstrates that Al3Ni2 phase nucleates and grows directly from the undercooled liquid. Meanwhile, the Debye temperatures of Al-47wt.%Ni alloy that fabricated at different pressures were also calculated using the low temperature heat capacity curve.

scholarly journals Nuclear Gamma Resonance Study of the Ir —Fe and Ir —Ni Alloy Systems

1971 ◽  
Vol 26 (3) ◽  
pp. 343-352 ◽  
Author(s):  
R.L. Mössbauer ◽  
M. Lengsfeld ◽  
W. Von Lieres ◽  
W. Potzel ◽  
T. Teschner ◽  
...  
Keyword(s):  
Composition Range ◽  
Magnetic Hyperfine Field ◽  
Band Model ◽  
Hyperfine Fields ◽  
Ni Alloys ◽  
Dilute Alloys ◽  
Ni Alloy ◽  
Bulk Magnetization ◽  
Bcc Phase ◽  
Alloy Systems

Abstract The Ir-Fe and Ir-Ni alloy systems were studied over the whole composition range by means of the nuclear resonance absorption of the 73 keV y-rays of 193Jr and of the 14.4 keV y-rays of 57Fe. The magnetic hyperfine field at the Ir-nuclei in Ir-Ni alloys decreases approximately linearly with the Ir concentration from - 460 kOe at 4.2 K in very dilute alloys to zero at about 20 at.-% Ir. This behaviour is paralleled by the decrease of the magnetic moment per Ni atom as determined from bulk magnetization measurements. The hyperfine fields at both Ir and Fe were measured for the ferromagnetic bcc phase of the Ir-Fe system. They turned out to be virtually independent of concentration with values of about -1400 kOe and - 330 kOe, respectively. Linewidths increasing with the Ir concentration indicate a distribution of hyperfine fields. The fee phase of the Ir-Fe system has been found to be paramagnetic at 4.2 K throughout the range of its existence. The dependence of the hyperfine fields on concentration is discussed in terms of a rigid 3d-band model combined with local shielding. A discussion of the concentration dependence of the 193Ir and 57Fe isomer shifts has to take into account lattice expansion as well as band repopulation effects.

Microstructure and Phase Selection of Undercooled Single-Phase Fe-Co Alloy

2010 ◽  
Vol 154-155 ◽  
pp. 1624-1628
Author(s):  
Ning Liu ◽  
Gen Cang Yang ◽  
Feng Liu
Keyword(s):  
Theoretical Calculation ◽  
Single Phase ◽  
Critical Value ◽  
Nucleation Theory ◽  
Experimental Result ◽  
Classical Nucleation Theory ◽  
Phase Selection ◽  
Maximum Undercooling ◽  
Bcc Phase ◽  
Selection Of

Fe-Co single-phase alloy melts with different Co contents were undercooled using fluxing method. The maximum undercooling DT = 457K (relative undercooling DT/Tm=0.259) was achieved in this work. At low undercooling (DT), single-phased microstructure was observed, but metastable bcc phase emerged in the as-solidified microstructure once DT exceeded a critical value, DTcrit. In the presence of classical nucleation theory, phase selection in the undercooled Fe-Co melt was investigated, and the theoretical calculation was coincided with the experimental result.

scholarly journals Investigation of Microstructure Evolution and Phase Selection of Peritectic Cuce Alloy During High-Temperature Gradient Directional Solidification

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 911
Author(s):  
Yiku Xu ◽  
Zhaohao Huang ◽  
Yongnan Chen ◽  
Junxia Xiao ◽  
Jianmin Hao ◽  
...  
Keyword(s):  
Directional Solidification ◽  
Primary Dendrite ◽  
Primary Phase ◽  
Withdrawal Rate ◽  
Compressive Property ◽  
Directionally Solidified ◽  
Phase Selection ◽  
Coupled Growth ◽  
Selection Of

In this work, a CuCe alloy was prepared using a directional solidification method at a series of withdrawal rates of 100, 25, 10, 8, and 5 μm/s. We found that the primary phase microstructure transforms from cellular crystals to cellular peritectic coupled growth and eventually, changes into dendrites as the withdrawal rate increases. The phase constituents in the directionally solidified samples were confirmed to be Cu2Ce, CuCe, and CuCe + Ce eutectics. The primary dendrite spacing was significantly refined with an increasing withdrawal rate, resulting in higher compressive strength and strain. Moreover, the cellular peritectic coupled growth at 10 μm/s further strengthened the alloy, with its compressive property reaching the maximum value of 266 MPa. Directional solidification was proven to be an impactful method to enhance the mechanical properties and produce well-aligned in situ composites in peritectic systems.

Formation and Phase Selection of CaCO 3 in the Intervention of Lignin Monomer Model Compounds

2021 ◽  
Vol 56 (4) ◽  
pp. 2000187
Author(s):  
Huifeng Hu ◽  
Fugen Liang ◽  
Haidong Zhu ◽  
Xiumei Zhang ◽  
Kecong Cui ◽  
...  
Keyword(s):  
Model Compounds ◽  
Phase Selection ◽  
Selection Of

Phase selection of titanium boride in copper matrix composites during solidification

2016 ◽  
Vol 52 (5) ◽  
pp. 2957-2963 ◽  
Author(s):  
Yihui Jiang ◽  
Dan Li ◽  
Shuhua Liang ◽  
Juntao Zou ◽  
Feng Liu
Keyword(s):  
Titanium Boride ◽  
Copper Matrix ◽  
Matrix Composites ◽  
Phase Selection ◽  
Copper Matrix Composites ◽  
Selection Of

Role of Hyperoxaluria/Hypercalciuria in Controlling the Hydrate Phase Selection of Pathological Calcium Oxalate Mineralization

2020 ◽  
Vol 21 (1) ◽  
pp. 683-691
Author(s):  
Jing Zhang ◽  
Lijun Wang ◽  
Wenjun Zhang ◽  
Christine V. Putnis
Keyword(s):  
Calcium Oxalate ◽  
Phase Selection ◽  
Hydrate Phase ◽  
Selection Of

scholarly journals Selection of the most adequate trip-modelling tool for integrated transport planning system

2016 ◽  
Vol 37 (1) ◽  
pp. 55-66 ◽  
Author(s):  
Piotr Sawicki ◽  
Marcin Kiciński ◽  
Szymon Fierek
Keyword(s):  
Selection Criteria ◽  
Selection Process ◽  
Regional Scale ◽  
Selection Procedure ◽  
Planning System ◽  
Second Phase ◽  
Transport Planning ◽  
Phase Selection ◽  
Technical Requirements ◽  
Selection Of

This paper deals with the problem of selection the most suitable trip-modelling tool (TMT), which is a part of the more complex integrated transport planning system (ITPS) at the regional scale. Since an application of TMT is not autonomous and several different users exist the selection problem is not a trivial. In this paper, an original five-phase selection procedure is presented. The first phase consists in specifica¬tion of both, detailed expectations of all identified users and technical requirements of ITPS. Second phase deals with research on available TMT while a third one is concentrated on defining a comprehensive set of criteria. In this phase critical criteria as well as selection criteria are defined. First one is utilised to eliminate unacceptable TMTs in phase four and second one to evaluate and select most adequate TMT in phase five. In the paper an exemplary application of this procedure is presented. The authors have defined 2 critical criteria and a set of 19 selection criteria. The last one is divided into 3 main subsets, i.e. functional, technical and financial contexts of selection process. All the selection criteria are characterised by 43 sub-criteria and some of them are more detailed extended. Using this procedure 3 out of 6 alternative TMTs including Emme, Aimsun and Visum have been initially accepted and next evaluated. Finally, Visum has been selected and recommended for application into ITPS.

Synthesis and Magnetic Properties of Nanocrystalline Co-Ni Alloys: A Review

2012 ◽  
Vol 736 ◽  
pp. 229-240 ◽  
Author(s):  
Sudhakar Panday ◽  
P. Jeevanandam ◽  
B.S. Sunder Daniel
Keyword(s):  
Magnetic Properties ◽  
Binary Alloys ◽  
Synthesis Method ◽  
Surface Oxidation ◽  
Alloy Nanoparticles ◽  
Ni Alloys ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Co Concentration ◽  
Potential Applications

This review article deals with the synthesis, characterization and magnetic properties of Co-Ni nanoalloys. The various physical and chemical methods for the synthesis of Co-Ni alloy nanoparticles are discussed. Co-Ni alloy nanoparticles with different size and shape such as spherical, rods, wires chain-like assembly are found to depend on the synthesis method and experimental condition. The structure of Co-Ni alloys is eitherfcc,hcpor mixedfccandhcpphase and found to depends on size, shape and concentration of Co in the Co-Ni alloys. Sodium hydroxide (NaOH) concentration and Co to Ni ratio influence the shape of bimetallic Co-Ni nanoparticles. Pt nucleating agents produced smaller size of Co-Ni alloy particles compared to Ru and Ag. Higher Co concentration in the Co-Ni alloys also influences the size alloy particles. The magnetic properties of Co-Ni nanoalloys depend on the size, shape and composition of the binary alloys. Surface oxidation of Co-Ni alloy nanoparticles decrease the saturation magnetization and increases with Co concentration in the alloys. The shape of Co-Ni alloy nanoparticles has an influence on coercivity. The microwave absorption properties of the Co-Ni alloys found to depend on the shape, size and composition of the binary alloys. The absorbance peaks shifts to higher frequency with decrease in size of the alloy particles. Potential applications of Co-Ni alloys in various fields are highlighted.

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