Factors influencing thermal conductivity and mechanical properties in 319 Al alloy cylinder heads

Vandersluis, Eli; Lombardi, Anthony; Ravindran, C.; Bois-Brochu, Alexandre; Chiesa, Franco; Mackay, Robert

doi:10.1016/j.msea.2015.09.091

Cited by 77 publications

(39 citation statements)

References 24 publications

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“…1c and 1d) feature Chinese-script Al 15 (Fe,Mn) 3 Si 2 , blocky and eutectic Al 2 Cu, and Al 5 Mg 8 Cu 2 Si 6 phases in the regions between the primary Al phase, as confirmed by EDS and XRD in a previous study of this alloy by the current authors (Vandersluis et al, 2015). On average, microstructures of this alloy consist of approximately 8% Si and 2% Al 2 Cu, independent of the solidification rate, as determined by area via quantitative image analysis software (Vandersluis, 2016). Owing to the difficulty in visually differentiating between the Fe-and Mg-containing phases, their combined area fraction was found to be 3%, although the predominant contribution to this measurement was from the Fe phase.…”

Section: Alloy Microstructuressupporting

confidence: 85%

“…After 10 min of settling time following the final addition for a given alloy, the melt was poured into an H13 tool steel permanent mould, preheated to 523 K, to produce simple 15 Â 3 Â 1 cm bar castings. The mould dimensions can be found in a previous study (Vandersluis, 2016). The average compositions of the castings and their associated standard deviations, determined using three optical emission spectrometry measurements, are presented in Table 1.…”

Section: Experimental Procedures 21 Preparation Of Alloysmentioning

confidence: 99%

“…However, additional alloying is typically used to promote a microstructure with many complex intermetallic phases that contribute towards enhanced bulk properties. For example, the A319 alloy, which is commonly used in the manufacture of automotive engine blocks and cylinder heads, features additional Cu-, Mg-and Fe-bearing secondary phases in the interdendritic regions (Vandersluis et al, 2015). These alloys are often further modified with trace additions of strontium (Sr) to transform the Si particle morphology from coarse and acicular to fine and fibrous, offering further improvements to elongation, strength and electrical conductivity (Fatahalla et al, 1999;Mulazimoglu et al, 1989).…”

Section: Introductionmentioning

confidence: 99%

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Determination of temperature-dependent crystallographic parameters of Al–Si alloys using in situ neutron diffraction

et al. 2018

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Accurate evaluation of temperature-dependent lattice spacings of individual phases in complex engineering alloys enables analysis and design of enhanced components for high-temperature applications. However, typical characterization techniques are limited to measurements at temperatures at which the alloy is completely solid state. In this study, in situ neutron diffraction was performed to determine the crystallographic parameters of several phases in unmodified and Sr-modified Al-6 wt% Si and A319 alloys from the start of solidification to 423 K. Approximately linear correlations were found for the interplanar spacings and lattice parameters of phases with temperature for the entire measured range. The greater concentration of lattice-contracting elements dissolved in the A319 solid solutions resulted in smaller lattice spacings and larger coefficients of thermal expansion than the same phases in Al-6 wt% Si, yet eutectic modification with Sr did not produce noticeable changes in the crystallographic parameters. The Si phase was found to have the largest thermal expansion coefficient misfit with the Al matrix. These findings offer significant insight into the development and mitigation of thermal stresses in the processing and operation of engineering components.

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Section: Alloy Microstructuressupporting

confidence: 85%

Section: Experimental Procedures 21 Preparation Of Alloysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Determination of temperature-dependent crystallographic parameters of Al–Si alloys using in situ neutron diffraction

et al. 2018

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“…Al-8Si alloy is modified by Sb and Sr to obtain fine flake and fibrous eutectic silicon. Spherical eutectic silicon can be obtained after T6 heat treatment, especially in the solid solution treatment stage, and the silicon phases break, spheroidize and grow, and the aspect ratio of silicon phase is increased [16,28]. Therefore, for the unmodified eutectic silicon in Figure 3a and the Sb modified eutectic silicon in Figure 3b-d after the T6 heat treatment, the long flake eutectic silicon is fractured or even spheroidized.…”

Section: Microstructurementioning

confidence: 99%

Effect of Modification with Different Contents of Sb and Sr on the Thermal Conductivity of Hypoeutectic Al-Si Alloy

Guo

Guan

Yan

et al. 2020

Metals

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In this paper, the effects of size, morphology and distribution of eutectic silicon on the thermal conductivity of Al-8Si alloy modified by Sr (0.04, 0.08, 0.12 wt.%) and Sb (0.1, 0.3, 0.5 wt.%) elements with T6 heat treatment were investigated. The results show that the modified fibrous eutectic silicon has a significant capability of improvement of thermal conductivity, while the amount of the modifier has a relatively weak effect on thermal conductivity. After T6 treatment, the fracture or spheroidization of the flake eutectic silicon and the disappearance of clustering phenomenon could raise thermal conductivity, but the coarsening of fibrous eutectic silicon is inconducive to thermal conductivity. Finally, the effect of eutectic silicon on electron transport is analyzed in detail, which could provide a reference for enhancing the thermal (or electrical) conductivity of hypoeutectic Al-Si alloy through effective microstructure control.

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“…Al-Si alloys usually present good thermal/electrical conductivity as well as excellent casting properties [1][2][3][4]. As a structural material, it has light-weight structural materials with low cost.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cooling Rate and Modification by Strontium on the Thermal Conductivity of Al-8Si Alloy

Wang

Guan

Wang

et al. 2021

Metals

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Cooling rate plays a critical role in determining the thermal conductivity of Al-Si alloys. Although the effect of morphology and size of Si (changed by heat treatment) on its thermal conductivity has been investigated, the effect of cooling rates on thermal conductivity has not been well studied. In this study, we investigated the microstructure of an Al-8Si (with and without modification by Strontium (Sr)) alloy with cooling rates from 46.2 °C/s to 234 °C/s. It was found that the effect of cooling rate on thermal conductivity of Sr modification and Sr-free samples are opposite from each other. As a result, while the cooling rate increased from 46.2 °C/s to 234 °C/s, the calculated thermal conductivity increased from 145.3 MS/m to 151.5 MS/m for Sr-free Al-8Si alloy, and the calculated thermal conductivity was reduced from 187.5 MS/m to 176.7 MS/m for the Sr-modified Al-8Si alloy. By discussing how thermal conductivity correlates with eutectic silicon morphology and secondary dendrite arm spacing, the relationship between cooling rate and thermal conductivity were explained. This work suggests a new design strategy for improving the thermal conductivity of Al-Si hypoeutectic alloys.

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Factors influencing thermal conductivity and mechanical properties in 319 Al alloy cylinder heads

Cited by 77 publications

References 24 publications

Determination of temperature-dependent crystallographic parameters of Al–Si alloys using in situ neutron diffraction

Determination of temperature-dependent crystallographic parameters of Al–Si alloys using in situ neutron diffraction

Effect of Modification with Different Contents of Sb and Sr on the Thermal Conductivity of Hypoeutectic Al-Si Alloy

Effect of Cooling Rate and Modification by Strontium on the Thermal Conductivity of Al-8Si Alloy

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