Effect of Dendrite Arm Spacing on Mechanical Properties of Aluminum Alloy Cylinder Heads and Engine Blocks

Samples of AlSi10Mg alloy were first constructed, selecting the manufacturing parameters through a parametric method based on an experimental design; with the same technique, samples of a metallic matrix composite (AlSi10Mg matrix base and particles of SiC reinforcements) were also made. The evolution of the density with the introduction of reinforcements into the AlSi10Mg alloy was studied. This showed an increase in the porosity level with the reinforcement volume fraction. The material hardness and electrical conductivity were then evaluated, along with conventional mechanical characteristics, and microstructural changes with respect to heat treatments on both the AlSi10Mg alloy material and AlSi10Mg matrix composite. Doing so allows correlating material hardness and electrical conductivity (as observed for conventionally produced alloys: casting or wrought). The tensile strength, yield strength and Young's modulus were measured. A significant increase in the conventional mechanical characteristics compared with casting was shown, due to hardening by structure refinement. Evidence is given to relate the yield strength value to the reduction in the dendrite arm spacing (DAS) by application of the Hall-Petch law. We discuss the understanding of the thermal process involved (temperature distribution and fast cooling rate). In addition, observations and analysis of the microstructural changes are presented: building tracks, the disturbed zone, and structural variations linked to heat treatment.

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“…The DAS for the AlSi10Mg alloy is evaluated at 0.5-0.6 μm ( Table 7 and Fig. 20) with the intercept method [19].…”

Section: Grain Size and Das (Alsi10mg Alloy)mentioning

confidence: 99%

Application study of AlSi10Mg alloy by selective laser melting: physical and mechanical properties, microstructure, heat treatments and manufacturing of aluminium metallic matrix composite (MMC)

Mauduit

Pillot

Frascati

2015

Metall. Res. Technol.

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“…On the other hand, the SDAS increases remarkably with a decrease in thickness. It has been reported by many researchers [4,6,7] that the SDAS relates to the cooling rate of the product. Generally, the higher the cooling rate the smaller the SDAS.…”

Section: Resultsmentioning

confidence: 98%

Permanent Mold Casting of JIS-AC4C Aluminum Alloy Using a Low-Temperature Mold

Yamagata¹,

Nikawa²

2011

AIP Conference Proceedings

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Permanent mold casting using mold temperatures below 200 C was conducted to obtain a high-strength, thin-walled casting. Al-7.36 mass% Si -0.18 Cu-0.27Mg-0.34Fe alloy JIS-AC4C was cast using a bottom pouring cast plan. The product had a rectangular tube shape (70 mm W x 68 mm D x 180 mm H) with wall thicknesses of 1, 3 and 5 mm. The effect of heat insulation at the melt path was compared when using a sand runner insert and when using a steel runner insert as well as a powder mold release agent. Fine microstructures were observed in the casting. The smaller the thickness, the higher the hardness with smaller secondary dendrite arm spacing (SDAS). However, the hardness and the SDAS were unaffected by the mold temperature. It was proposed that the avoidance of the formation of primary  dendrite at the melt path generates a higher strength casting with adequate mold filling.

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“…The scatter in the deformation behaviour between replicas can possibly be attributed to the difference in the microstructural variation between the samples, the inter-dendritic arm spacing in particular, which varies significantly even within the cylinder head structure. Numerous studies have shown the effect of the variation of the dendritic arm spacing on the resulting deformation properties [2,14,[36][37][38].…”

Section: Monotonic Deformationmentioning

confidence: 99%

“…The dendritic arm spacing primarily determined by the local cooling rate governs the ductility and strength of the material in the structure [13]. Since a complex structure like a cylinder head has varying solidification rates in different regions, the resultant microstructure and deformation behaviour have a high degree of variability within the structure [13,14].…”

Section: Introductionmentioning

confidence: 99%

Effect of Temperature on Deformation and Fatigue Behaviour of A356–T7 Cast Aluminium Alloys Used in High Specific Power IC Engine Cylinder Heads

et al. 2020

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Aggressive downsizing of the internal combustion engines used as part of electrified powertrains in recent years have resulted in increasing thermal loads on the cylinder heads and consequently, the susceptibility to premature thermo-mechanical fatigue failures. To enable a reliable computer aided engineering (CAE) prediction of the component lives, we need more reliable material deformation and fatigue performance data. Material for testing was extracted from the highly loaded valve bridge area of specially cast cylinder heads to study the monotonic and cyclic deformation behaviour of the A356–T7 + 0.5% Cu alloy at various temperatures. Monotonic tensile tests performed at different temperatures indicate decreasing strength from 211 MPa at room temperature to 73 MPa at 300 °C and a corresponding increase in ductility. Completely reversed, strain controlled, uniaxial fatigue tests were carried out at 150, 200 and 250 °C. A dilatometric study carried out to study the thermal expansion behaviour of the alloy in the temperature range 25–360 °C shows a thermal expansion coefficient of (25–30) × 10−6 °C−1. Under cyclic loading, increasing plastic strains are observed with increasing temperatures for similar load levels. The experimental data of the cyclic deformation behaviour are calibrated against a nonlinear combined kinematic–isotropic hardening model with both a linear and non-linear backstress.

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Effect of Dendrite Arm Spacing on Mechanical Properties of Aluminum Alloy Cylinder Heads and Engine Blocks

Cited by 11 publications

References 5 publications

Application study of AlSi10Mg alloy by selective laser melting: physical and mechanical properties, microstructure, heat treatments and manufacturing of aluminium metallic matrix composite (MMC)

Application study of AlSi10Mg alloy by selective laser melting: physical and mechanical properties, microstructure, heat treatments and manufacturing of aluminium metallic matrix composite (MMC)

Permanent Mold Casting of JIS-AC4C Aluminum Alloy Using a Low-Temperature Mold

Effect of Temperature on Deformation and Fatigue Behaviour of A356–T7 Cast Aluminium Alloys Used in High Specific Power IC Engine Cylinder Heads

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