Thermal expansion of the V5Si3 and T2 phases of the V–Si–B system investigated by high-temperature X-ray diffraction

Rodrigues, Geovani; Nunes, Carlos Ângelo; Suzuki, Paulo Atsushi; Coelho, Gilberto Carvalho

doi:10.1016/j.intermet.2009.03.006

Cited by 10 publications

(7 citation statements)

References 27 publications

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“…Currently, using a larger supercell for AIMD will be computationally prohibitive, (4) There may be experimental uncertainty with respect to the CTE values themselves. For example, using a wider temperature range (up to 1400K), Rodrigues et al [26] reported CTE values for V 5 Si 3 closer to our results [ Fig. 4(b)].…”

Section: Coefficent Of Thermal Expansion (Cte) and Thermal Expansion supporting

confidence: 89%

In search of zero thermal expansion anisotropy in Mo5Si3 by strategic alloying

Dharmawardhana

Sakidja

Aryal

et al. 2015

Journal of Alloys and Compounds

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Reducing the thermal expansion anisotropy (TEA) of alloy compounds is one of the most important issues for their potential applications in high temperature environment. The Mo 5 Si 3 (T1 phase) is known to be an important intermetallic compound with high melting temperature. Unfortunately, its large TEA renders it unsuitable for high temperature structural/coating applications. Many attempts have been made in the past to reduce TEA by substituting Mo by other transition metal ions such as V with little success and some unexpected observations. Here we use accurate ab-initio molecular dynamics (AIMD) simulations to obtain the TEA from thermal expansion coefficients for two T1 phase alloy systems (Mo,V) 5 Si 3 and Mo 5 (Si,Al) 3 . We demonstrate that strategic alloying with Al substituting Si can achieve zero TEA for T1 phase. The microscopic origin of this outstanding thermomechanical properties in this alloy is explained by the calculation of higher order elastic constants in conjunction with atom and directionresolved phonon density of states.

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Section: Coefficent Of Thermal Expansion (Cte) and Thermal Expansion supporting

confidence: 89%

In search of zero thermal expansion anisotropy in Mo5Si3 by strategic alloying

Dharmawardhana

Sakidja

Aryal

et al. 2015

Journal of Alloys and Compounds

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“…The pistons are made from multicomponent AleSi alloys, and there is a significant need to improve the processing and mechanical properties of these alloys as a result of increasing performance demands. The presence of additional elements in the AleSi alloy system allows many complex intermetallic phases to form, which include, for example, Al 2 Cu, Al 3 Ni, Al 3 Ni 2 , Al 7 Cu 4 Ni, Al 9 FeNi and aAlFeMnSi phases, all of which may have some solubility for additional elements [1]. Most automotive piston engines are currently running at service temperatures of up to 350 C, with diesel engines running even hotter.…”

Section: Introductionmentioning

confidence: 99%

Study on thermal expansion of intermetallics in multicomponent Al–Si alloys by high temperature X-ray diffraction

Chen

Thomson

2010

Intermetallics

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“…The PANalytical X'Pert HighScore Plus [104] crystallographic analysis software database was used in conjunction with the expected phase compositions of this alloy to identify nine peaks in the intensity plot. In both the unmodified A319 and modified A319 + Sr alloys, the Si (111), Al5Mg8Cu2Si6 (121), Al (111), Al15(Fe,Mn)3Si2 (530), Al (200), Si (220), Al2Cu (310), Si (311), and Al (220) planes were identified at approximate diffraction angles of 44°, 54°, 60°, 66°, 71°, 76°, 77°, 93° and 110°, respectively. Whereas the peaks for the Al and Si phases were prominent in the diffraction plots, the peaks for the Mg-, Fe-, and Cu-containing phases were quite weak, corresponding to their relatively low volume fractions in the alloy.…”

Section: 3-31 In-situ Neutron Diffraction Resultsmentioning

confidence: 99%

“…In addition to determining differences in coefficients of thermal expansion, the measurement of crystallographic parameters has been the focus of many research papers that aim to construct equations of state that satisfactorily define the variation of material properties with temperature. Most commonly, this has been achieved using x-ray diffraction methods, which enable the concurrent evaluation of the lattice expansion of each of the individual phases in complex alloys [119][120][121][122]. However, due to their interaction with atomic electron clouds, x-rays have a relatively low penetration depth and are limited to obtaining surface properties [52].…”

Section: 4-1 Introductionmentioning

confidence: 99%

Mechanisms of Improving the Thermal and Electrical Conductivity of Aluminum Alloy Cylinder Heads

Vandersluis¹

2023

Preprint

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<p>One of the major causes of premature failure in automotive cylinder heads is the accumulation of thermal stresses, due to their large internal temperature gradients in-service. To ensure mechanical integrity, engine operating temperatures are typically restricted. However, this response reduces fuel efficiency, which increases costs and carbon emissions. A more sustainable solution can involve enhancing alloy conductivity, which improves temperature uniformity in the heads. In aluminum alloys, solidification rate, silicon modification, and precipitation heat treatment have each been reported to influence conductivity. Yet, the mechanisms and interactions regarding these parameters were unclear in the literature. Accordingly, the objective of this dissertation was to provide an in-depth, systematic investigation of the individual and combined effects of these processes on the microstructure and conductivity of automotive 319 aluminum alloy.</p> <p>After performing a baseline characterization of commercial cylinder heads, permanent-mould castings were produced with a range of solidification rates and strontium contents. These castings were analyzed to establish the dominant microstructural factors affecting electron mobility in the as-cast condition. Then, samples were subjected to multiple combinations of solution, natural aging, artificial aging, and direct aging heat treatments, to elucidate the roles of the dissolution, spheroidization and precipitation transformations. Furthermore, this work was complimented by several innovative, state-of-the-art experiments, which were the first to analyze the kinetics of solidification, chemical modification, thermal expansion, dissolution, and precipitation in 319. As a result, this dissertation contributed numerous, novel and meaningful insights regarding heat transfer in aluminum alloys. This included elucidation of the independent, major impacts of porosity, silicon morphology, and the size, distribution and coherency of the aluminum-copper precipitates, despite insensitivity to the dendritic size. The appropriate combination of solidification rate, strontium content, and heat treatment was demonstrated to promote superior conductivity to what was possible through their individual variation. Given low-porosity castings, this research revealed the potential for approximately 40% improvements in thermal and electrical conductivity, compared to the strontium-free, as-cast condition. Overall, the extensive conductivity data generated in this research supports strategic and practical materials processing procedures, demonstrates opportunities for balancing high conductivity with mechanical integrity, and ensures enhanced component performance and environmental sustainability.</p>

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Thermal expansion of the V5Si3 and T2 phases of the V–Si–B system investigated by high-temperature X-ray diffraction

Cited by 10 publications

References 27 publications

In search of zero thermal expansion anisotropy in Mo5Si3 by strategic alloying

In search of zero thermal expansion anisotropy in Mo5Si3 by strategic alloying

Study on thermal expansion of intermetallics in multicomponent Al–Si alloys by high temperature X-ray diffraction

Mechanisms of Improving the Thermal and Electrical Conductivity of Aluminum Alloy Cylinder Heads

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