scholarly journals Effect of High Pressure on the Solidification of Al–Ni Alloy

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 478
Author(s):  
Xiao-Hong Wang ◽  
Duo Dong ◽  
Xiao-Hong Yang
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Potential Energy ◽  
Ambient Pressure ◽  
Interface Temperature ◽  
Debye Temperatures ◽  
Ni Alloy ◽  
Low Temperature Specific Heat ◽  
Al3ni Phase ◽  
Dendrite Growth Model

The effect of high pressure on the microstructure of hypo-peritectic Al–38wt.%Ni alloy was studied. The results show that Al3Ni and Al3Ni2 phases coexist at ambient pressure. However, it becomes a typical hyper-eutectic microstructure when synthesized at 2 GPa and 4 GPa. Meanwhile, the interface temperature of Al3Ni and Al3Ni2 phases was calculated with the combination of the BCT dendrite growth model, which is suitable for the Al3Ni2 phase. According to the highest interface temperature principle, the result shows that the Al3Ni phase dominates over 1–5 GPa. Finally, the Debye temperature and potential energy of the hypo-peritectic Al–38wt.%Ni alloy under different pressures were researched. Based on the low temperature specific heat-capacity curve. The Debye temperatures at ambient pressure, 2 GPa, and 4 GPa are 504.4 K, 508.71 K and 515.36 K, respectively, and the potential energy in the lowest point decreases with the increase of pressure.

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.

The formation of bulk β-Al3Ni phase in eutectic Al-5.69wt%Ni alloy solidified under high pressure

2018 ◽  
Vol 742 ◽  
pp. 670-675 ◽  
Author(s):  
X.H. Wang ◽  
Z. Ran ◽  
Z.J. Wei ◽  
C.M. Zou ◽  
H.W. Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Ni Alloy ◽  
Al3ni Phase

Development of frequency tuning AC modulation method for high-pressure heat capacity measurements of molecules-based compounds

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040062
Author(s):  
T. Nomoto ◽  
T. Maruyama ◽  
S. Yamashita ◽  
H. Akutsu ◽  
Y. Nakazawa
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Frequency Tuning ◽  
Ambient Pressure ◽  
Heat Bath ◽  
Modulation Method ◽  
Automatic Frequency ◽  
Ac Calorimetry ◽  
Frequency Changes ◽  
Heat Capacity Measurements

The automatic frequency tuning method in the high-pressure ac calorimetry system constructed to measure heat capacity for molecules-based compounds with CuBe[Formula: see text]+[Formula: see text]NiCrAl cramp-type pressure cell is reported. This development is performed for increasing resolution and temperature ranges of the heat capacity measurements under external pressure up to 2.0 GPa. The system can check the appropriate conditions by tracing frequency dependence of [Formula: see text] to determine the oscillation frequency at the center of the plateau region of this value. The experiments using the powder samples of metal complexes clarified that the appropriate frequency changes sensitively depending on the difference of temperature and that of external pressures, especially at low temperature region. It decreases with increasing temperature and this relation was found to be almost linear with temperature in ambient pressure and under pressure conditions. The change of thermal diffusion from the sample part to the heat bath should be treated carefully in order to get enough resolution in high pressure AC heat capacity measurements of molecule-based compounds.

The effects of high pressure and superheating on the planar growth of Al3Ni phase in hypo-peritectic Al-30wt%Ni alloy

2019 ◽  
Vol 772 ◽  
pp. 1052-1060 ◽  
Author(s):  
X.H. Wang ◽  
H.W. Wang ◽  
C.M. Zou ◽  
Z.J. Wei ◽  
Y. Uwatoko ◽  
...  
Keyword(s):  
High Pressure ◽  
Ni Alloy ◽  
Planar Growth ◽  
Al3ni Phase

scholarly journals Structure, Morphology, Heat Capacity, and Electrical Transport Properties of Ti3(Al,Si)C2 Materials

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3222
Author(s):  
Kamil Goc ◽  
Janusz Przewoźnik ◽  
Katarzyna Witulska ◽  
Leszek Chlubny ◽  
Waldemar Tokarz ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Heat Capacity ◽  
Specific Heat ◽  
Electrical Transport ◽  
Residual Resistivity ◽  
Max Phase ◽  
Electrical Transport Properties ◽  
Debye Temperatures ◽  
Si Content ◽  
Hot Pressing Sintering

A study of Ti3Al1−xSixC2 (x = 0 to x = 1) MAX-phase alloys is reported. The materials were obtained from mixtures of Ti3AlC2 and Ti3SiC2 powders with hot pressing sintering technique. They were characterised with X-ray diffraction, heat capacity, electrical resistivity, and magnetoresistance measurements. The results show a good quality crystal structure and metallic properties with high residual resistivity. The resistivity weakly varies with Si doping and shows a small, positive magnetoresistance effect. The magnetoresistance exhibits a quadratic dependence on the magnetic field, which indicates a dominant contribution from open electronic orbits. The Debye temperatures and Sommerfeld coefficient values derived from specific heat data show slight variations with Si content, with decreasing tendency for the former and an increase for the latter. Experimental results were supported by band structure calculations whose results are consistent with the experiment concerning specific heat, resistivity, and magnetoresistance measurements. In particular, they reveal that of the s-electrons at the Fermi level, those of Al and Si have prevailing density of states and, thus predominantly contribute to the metallic conductivity. This also shows that the high residual resistivity of the materials studied is an intrinsic effect, not due to defects of the crystal structure.

scholarly journals High-Pressure Synthesis of Non-Stoichiometric LixWO3 (0.5 ≤ x ≤ 1.0) with LiNbO3 Structure

Inorganics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 63
Author(s):  
Kohdai Ishida ◽  
Yuya Ikeuchi ◽  
Cédric Tassel ◽  
Hiroshi Takatsu ◽  
Craig M. Brown ◽  
...  
Keyword(s):  
High Pressure ◽  
Perovskite Phase ◽  
Ambient Pressure ◽  
Tungsten Bronze ◽  
Type Structure ◽  
High Pressure Synthesis ◽  
Phase 0 ◽  
Pressure Synthesis ◽  
Octahedral Tilting ◽  
Recent Attention

Compounds with the LiNbO3-type structure are important for a variety of applications, such as piezoelectric sensors, while recent attention has been paid to magnetic and electronic properties. However, all the materials reported are stoichiometric. This work reports on the high-pressure synthesis of lithium tungsten bronze LixWO3 with the LiNbO3-type structure, with a substantial non-stoichiometry (0.5 ≤ x ≤ 1). Li0.8WO3 exhibit a metallic conductivity. This phase is related to an ambient-pressure perovskite phase (0 ≤ x ≤ 0.5) by the octahedral tilting switching between a−a−a− and a+a+a+.

Dynamic High Pressure: a novel approach toward near ambient pressure photoemission spectroscopy and spectromicroscopy

2013 ◽  
Vol 8 (05) ◽  
pp. T05001-T05001 ◽  
Author(s):  
M Amati ◽  
M Kazemian Abyaneh ◽  
L Gregoratti
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Photoemission Spectroscopy ◽  
Novel Approach ◽  
Dynamic High Pressure

Intermolecular Potential Energy of Dipolar Gases from Heat Capacity Data

1955 ◽  
Vol 23 (12) ◽  
pp. 2453-2454 ◽  
Author(s):  
D. R. Douslin ◽  
Guy Waddington
Keyword(s):  
Heat Capacity ◽  
Potential Energy ◽  
Heat Capacity Data ◽  
Intermolecular Potential ◽  
Dipolar Gases ◽  
Capacity Data

scholarly journals Pressure-Dependent Clustering in Ionic-Liquid-Poly (Vinylidene Fluoride) Mixtures: An Infrared Spectroscopic Study

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2099
Author(s):  
Teng-Hui Wang ◽  
Wei-Xiang Wang ◽  
Hai-Chou Chang
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Vinylidene Fluoride ◽  
Ambient Pressure ◽  
Infrared Spectroscopic Study ◽  
Research Attention ◽  
Nanoscale Structures ◽  
Local Structures ◽  
Poly Vinylidene Fluoride ◽  
Hydrogen Bonded

The nanostructures of ionic liquids (ILs) have been the focus of considerable research attention in recent years. Nevertheless, the nanoscale structures of ILs in the presence of polymers have not been described in detail at present. In this study, nanostructures of ILs disturbed by poly(vinylidene fluoride) (PVdF) were investigated via high-pressure infrared spectra. For 1-(2-hydroxyethyl)-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([HEMIm][TFSI])-PVdF mixtures, non-monotonic frequency shifts of the C4,5-H vibrations upon dilution were observed under ambient pressure. The experimental results suggest the presence of microheterogeneity in the [HEMIm][TFSI] systems. Upon compression, PVdF further influenced the local structure of C4,5–H via pressure-enhanced IL–PVdF interactions; however, the local structures of C2–H and hydrogen-bonded O–H were not affected by PVdF under high pressures. For choline [TFSI]–PVdF mixtures, PVdF may disturb the local structures of hydrogen-bonded O–H. In the absence of the C4,5–H⋯anion and C2–H⋯anion in choline [TFSI]–PVdF mixtures, the O–H group becomes a favorable moiety for pressure-enhanced IL–PVdF interactions. Our results indicate the potential of high-pressure application for designing pressure-dependent electronic switches based on the possible changes in the microheterogeneity and electrical conductivity in IL-PVdF systems under various pressures.

scholarly journals Fuel spray vapour distribution correlations for a high pressure diesel fuel spray cases for different injector nozzle geometries.

2017 ◽  
Author(s):  
Darlington Njere ◽  
Nwabueze Emekwuru
Keyword(s):  
High Pressure ◽  
Liquid Phase ◽  
Diesel Fuel ◽  
Ambient Pressure ◽  
Vapour Phase ◽  
Fuel Spray ◽  
Combustion Chambers ◽  
Complete Combustion ◽  
Fuel Injectors ◽  
Fuel Vapour

The evolution of diesel fuel injection technology, to facilitate strong correlations of in-cylinder spray propagation with injection conditions and injector geometry, is crucial in facing emission challenges. More observations of spray propagation are, therefore, required to provide valuable information on how to ensure that all the injected fuel has maximum contact with the available air, to promote complete combustion and reduce emissions. In this study, high pressure diesel fuel sprays are injected into a constant-volume chamber at injection and ambient pressure values typical of current diesel engines. For these types of sprays the maximum fuel liquid phase penetration is different and reached sooner than the maximum fuel vapour phase penetration. Thus, the vapour fuel could reach the combustion chamber wall and could be convected and deflected by swirling air. In hot combustion chambers this impingement can be acceptable but this might be less so in larger combustion chambers with cold walls. The fuel-ambient mixture in vapourized fuel spray jets is essential to the efficient performance of these engines. For this work, the fuel vapour penetration values are presented for fuel injectors of different k-factors. The results indicate that the geometry of fuel injectors based on the k-factors appear to affect the vapour phase penetration more than the liquid phase penetration. This is a consequence of the effects of the injector types on the exit velocity of the fuel droplets.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4951

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