Effects of high pressure and SiC content on microstructure and precipitation kinetics of Al–20Si alloy

Ma, Peijun; Zou, Chaoying; Wang, H.W.; Scudino, Sergio; Fu, Bin-guo; Wei, Zunjie; Kühn, U.; Eckert, J.

doi:10.1016/j.jallcom.2013.10.128

Cited by 42 publications

(10 citation statements)

References 42 publications

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“…Yu et al reported that the ascendant tendency of the solid phase line, liquid phase line, and eutectic temperature line were detected with the increasing pressure, leading to the right shifting of the eutectic point, e.g., the Si content of eutectic point is ≈31 wt% with the pressure increasing up to 5.0 GPa. [ 41 ] According to the related research, the main features of the high pressure solidification/solution treatment on the shifting of the eutectic points can be summarized as follows: [ 19,41,42 ] 1) enhanced solid solubility: the solid solubility of Al–Si alloy increases because the velocity of atomic diffusion decreases under high pressure solidification, which has been reported by Yu et al 2) Lower nucleation energy: the decrease in the critical formation energy of the nucleation could be found with an increase in pressure, leading to the emergence of more sites for nucleation, which is positive for refinement of eutectic structure, as reported by Ma et al 3) Lower diffusion rate: the diffusivity of Si phase decreased under high pressure, which resulted from the decrease in the diffuse velocity.…”

Section: Discussionmentioning

confidence: 99%

Toward Enhanced Strength and Ductility of Al–14.5Si Alloy via Solidification Under Super‐Gravity Field

et al. 2020

Adv Eng Mater

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Herein, a novel method to improve the mechanical properties of Al–14.5Si alloys via solidification under super‐gravity field is reported. The Al–14.5Si alloys are solidified under normal gravity (1 g) and various super‐gravity fields (1000 g, 2000 g, 3000 g, and 4000 g), respectively. The results indicate that the solidification under super‐gravity field leads to right shifting of eutectic point and significant refinement of the eutectic Si. The refining of eutectic Si has a tremendous influence on mechanical properties. The elongation and fracture toughness of the Al–14.5Si alloys, solidified under super‐gravity field of 3000 g, can reach up to ≈12.7% and ≈20.21 MPa, which are approximately tenfold and three times higher relative to those under normal gravity, respectively. The fracture mode of Al–14.5Si alloy is transformed from brittle fracture under normal gravity to ductile fracture under super‐gravity field.

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Section: Discussionmentioning

confidence: 99%

Toward Enhanced Strength and Ductility of Al–14.5Si Alloy via Solidification Under Super‐Gravity Field

et al. 2020

Adv Eng Mater

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“…Therefore, the exact number of Si clusters cannot be determined, and only the solid solubility of Si in the α-Al phase can be roughly estimated. Based on the lattice parameters of the Al phase, the solubility of Si in the Al-20Si alloys is 1.85, 5.27, and 6.73 at.% at 1, 2, and 3 GPa, respectively [23]. Compared to the Al-20Si alloys, the solubility of Si is slightly higher in the SiC/Al-50Si composites, indicating that the higher Si content in the matrix increases the solubility of Si under high pressure.…”

Section: Nano-phase Precipitationmentioning

confidence: 99%

Nano-Phase and SiC–Si Spherical Microstructure in SiC/Al-50Si Composites Solidified under High Pressure

et al. 2023

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The formation of coarse primary Si is the main scientific challenge faced in the preparation of high-Si Al matrix composites. The SiC/Al-50Si composites are prepared by high pressure solidification, which allows the primary Si to form a SiC–Si spherical microstructure with SiC, while the solubility of Si in Al is increased by high pressure to reduce the proportion of primary Si, thus enhancing the strength of the composites. The results show that the high melt viscosity under high pressure makes the SiC particles almost “fixed” in situ. The SEM analysis shows that the presence of SiC in the growth front of the primary Si will hinder its continued growth and eventually form SiC–Si spherical microstructure. Through aging treatment, a large number of dispersed nanoscale Si phases are precipitated in the α-Al supersaturated solid solution. The TEM analysis shows that a semi-coherent interface is formed between the α-Al matrix and the nanoscale Si precipitates. The three-point bending tests shows that the bending strength of the aged SiC/Al-50Si composites prepared at 3 GPa is 387.6 MPa, which is 18.6% higher than that of the unaged composites.

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“…In addition, the hardness of the alloy increases with the application of pressure. This enhanced behavior in HPSC and LPSC alloys in comparison with GDC alloy was due to improvements in heat transfer rates during solidification due to the applied pressure, resulting in refinement of microstructure and the improved contact area between the die and molten metal surface [50,51,60,61].…”

Section: Hardnessmentioning

confidence: 99%

Mechanical and Tribological Behavior of Gravity and Squeeze Cast Novel Al-Si Alloy

Chandra

Krishna

Ravi

et al. 2022

Metals

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The automotive industry traditionally reduces weight primarily by value engineering and thickness optimization. However, both of these strategies have reached their limits. A 6% reduction in automotive truck mass results in a 13% improvement in freight mass. Aluminum alloys have lower weight, relatively high specific strength, and good corrosion resistance. Therefore, the present manuscript involves manufacturing Al-based alloy by squeeze casting. The effect of applied pressure during the squeeze cast and gravity cast of a novel Al-Si alloy on microstructural evolution, and mechanical and wear behavior was investigated. The results demonstrated that squeeze casting of the novel Al-Si alloy at high-pressure exhibits superior mechanical properties and enhanced wear resistance in comparison to the gravity die-cast (GDC) counterpart. Squeeze casting of this alloy, at high pressure, yields fine dendrites and reduced dendritic arm spacing, resulting in grain refinement. The finer dendrites and reduced dendritic arm spacing in high-pressure squeeze cast alloy than in the GDC alloy were due to enhanced cooling rates observed during the solidification process, as well as the applied squeeze pressure breaks the initial dendrites that started growing during the solidification process. Reduced casting defects in the high-pressure squeeze cast alloy led to a reduced coefficient of friction, resulting in improved wear resistance even at higher loads and higher operating temperatures. Our results demonstrated that squeeze casting of the novel Al-Si alloy at high-pressure exhibits a 47% increase in tensile strength, 33% increase in hardness, 10% reduction in coefficient of friction, and 15% reduction in wear loss compared to the GDC counterpart.

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Effects of high pressure and SiC content on microstructure and precipitation kinetics of Al–20Si alloy

Cited by 42 publications

References 42 publications

Toward Enhanced Strength and Ductility of Al–14.5Si Alloy via Solidification Under Super‐Gravity Field

Toward Enhanced Strength and Ductility of Al–14.5Si Alloy via Solidification Under Super‐Gravity Field

Nano-Phase and SiC–Si Spherical Microstructure in SiC/Al-50Si Composites Solidified under High Pressure

Mechanical and Tribological Behavior of Gravity and Squeeze Cast Novel Al-Si Alloy

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