Effects of Sr and pressure on microstructure, mechanical and wear properties of near eutectic Al–Si piston alloys

Pratheesh, K.; Ravi, M.; Kanjirathinkal, Allesu; Joseph, M. A.

doi:10.1179/1743133615y.0000000016

Cited by 20 publications

(4 citation statements)

References 18 publications

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“…The adequate addition of nickel (Ni), as well as Mg and Cu, and the application of heat treatments, can increase mechanical strength, wear resistance and even ductility of Al-Si alloys due to solid solution hardening [165]. Also, the addition of Ni is believed to improve corrosion resistance [55].…”

Section: Other Transition Elementsmentioning

confidence: 99%

The Influence of Alloying Elements on the Microstructure and Properties of Al-Si-Based Casting Alloys: A Review

Callegari

Lima

Coelho

2023

Metals

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The excellent casting behavior and mechanical and corrosion properties of aluminum-silicon (Al-Si)-based alloys make them ideal for the manufacture of lightweight components with complex geometries. However, these properties depend directly on their microstructure, which, in its turn, is strongly affected by the composition of the alloy, among other factors. Several elements can be added to the material aiming to promote microstructural changes, e.g., grain refinement, optimization of phase morphology and distribution, and precipitation strengthening. Efforts are continuously put into such enhancements of cast Al alloys since they lead to quality improvements that allow for weight reduction and safety increase. Considering the technological relevance of the subject, this paper provides an overview of the research focused on the addition of alloying elements to these alloys, with a greater focus on Al-Si-based systems and the comprehension of the effects of these additions on their microstructure and properties.

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Section: Other Transition Elementsmentioning

confidence: 99%

The Influence of Alloying Elements on the Microstructure and Properties of Al-Si-Based Casting Alloys: A Review

Callegari

Lima

Coelho

2023

Metals

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“…It is worth noting that such a comparison of tensile properties is based on values for the studied alloy in the as-cast condition, that is, only affected by the solidification cooling rate. In contrast, the values related to the Al-Si-Cu-Mg-Ni piston alloys are affected by the use of Sr as a refining agent, [46] heat treatment, [46] ultrasonic agitation, [47] and addition of new alloying elements. [48][49][50] Thus, in terms of tensile properties, the eutectic Al-Si-Ni alloy has proven its potential for manufacturing of pistons.…”

Section: Resultsmentioning

confidence: 99%

Morphology of Intermetallics Tailoring Tensile Properties and Quality Index of a Eutectic Al–Si–Ni Alloy

2020

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The Al-Si-Ni alloy system is a source of multicomponent piston alloys, which combine good castability and wear resistance of Al-Si alloys with great thermal stability and corrosion resistance of Al-Ni alloys. [1-3] The inherent high piston temperature during engine functioning is one of the limiting factors for the application of Al-Si-based alloys. [4] On the other hand, alloys containing Al-Ni-based intermetallic compounds (IMCs) are mainly used for high-temperature structural products, which also demand wear resistance, such as aircraft engines, turbine vanes, and guide vanes of industrial steam turbines. [5,6] The formation of Ni-rich IMCs occurs even for low Ni concentrations, [7] as Ni is almost insoluble in aluminum, with a solubility of about 0.05 wt% at 640 ºC and less than 0.005 wt% at 450 ºC. [8] Thus, the addition of Ni to Al─Si alloys can potentially improve their wear resistance at elevated temperatures. Once the second phases are responsible for these characteristics, the modification of the microstructure, regarding its refinement, usually improves the properties and extends the lifetime of the component. Apart from the formation of different IMCs, the addition of new alloying elements can promote modification of other phases, mainly on Si. Kaya and Aker [9] studied ternary Al-12.6 wt% Si-2 wt% X alloys, where X was Cu, Co, Ni, Sb, or Bi. They verified that the addition of Co promotes a better distribution of Si flakes (i.e., smallest interflake spacings) and, consequently, highest hardness and tensile strength are achieved. Although the addition of Cu induced the least efficient refinement effect, the Al-12.6 wt% Si-2 wt% Cu alloy showed the second highest tensile properties. This occurred probably due to the formation of a supersaturated solid solution and hard Al 2 Cu particles. As Al 2 Cu and Al 9 Co 2 have similar hardness (588 [10] and 568 HV, [11] respectively), and Co is restricted to the formation of Al 9 Co 2 , the refinement of Si seems to have a major effect on mechanical properties. The aforementioned alloying elements are not modifiers of the eutectic Si morphology, but they just decrease the interflake spacing. Sr is a strong modifier, which is capable of transforming the acicular Si in welldistributed fibers with only a few hundred parts per million. In an Al-10 wt% Si alloy, 240 ppm of Sr has the same effect as 520 ppm of Ti-B grain refiner in terms of tensile properties. [12] Another Si modifier, Sc, also decreases the secondary dendritic arm spacing and refines the grain size; however, it requires an amount 20 times greater than that of Sr to improve the mechanical properties at the same level. [13] In secondary aluminum, Mn, [14,15] Cr, [16,17] Ni, [18,19] and other alloying elements are added to suppress the precipitation of harmful β-AlFeSi, aiming at the formation of α-AlFeSi, which has a Chinese-script morphology. Even though modification is, in general, desirable, excessive addition can lead to overmodification. Riestra et al. [20] observed in Al-11 wt% Mg 2 Si alloys, in ...

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“…To minimize the side effect of Sr addition, proper selection of casting processes becomes essential and critical, in which the advantages of alloying elements in AlÀ Si alloys could be maximized. Squeeze casting, also known as liquid metal forging, extrusion casting and pressure crystallization, has become an emerging technology for manufacturing light weight components alloy with aluminum and magnesium alloys [27][28][29][30][31][32][33][34][35][36][37][38]. This is because the process involves the solidification of a molten metal in a closed die under an imposed high pressure which keeps entrapped gases in solution and squeeze molten metal from hot spots to incipient shrinkage pores.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ni and Sr on the microstructure and tensile properties of the squeeze cast Al‐Si‐Cu alloy at elevated temperatures

Fang,

Hu,

Shen

et al. 2024

Materialwissenschaft Werkst

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The influence of the transition alloying element nickel and the alkaline earth element strontium on the microstructure and tensile properties of squeeze cast Al−Si‐Cu alloy under as‐cast condition at elevated temperature of 100 °C, 200 °C and 300 °C is investigated in comparison with the conventional Al−Si‐Cu alloy (A380). Aluminum alloy A380 is alloyed and modified with 2 wt% additional nickel (Ni) and 0.02 wt% strontium (Sr). Squeeze casting is employed to cast the modified A380 under an applied pressure of 90 MPa. The results of tensile testing at the selected elevated temperatures indicate that the Ni and Sr containing A380 alloy exhibits a significantly improvement on tensile properties, specifically ultimate tensile strength and yield strength with 10 %‐30 % increases. The as‐cast microstructures of both the conventional and Ni and Sr‐containing alloys are observed by an optical microscope and further analyzed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The presence of Ni‐containing intermetallic phases with Ni addition, and the modified eutectic Si phase with refined morphologies due to the Sr addition should be responsible for the considerable enhancement on the as‐cast strengths of the squeeze cast Ni‐ and Sr‐containing alloy over those of the conventional A380 alloy.

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Effects of Sr and pressure on microstructure, mechanical and wear properties of near eutectic Al–Si piston alloys

Cited by 20 publications

References 18 publications

The Influence of Alloying Elements on the Microstructure and Properties of Al-Si-Based Casting Alloys: A Review

The Influence of Alloying Elements on the Microstructure and Properties of Al-Si-Based Casting Alloys: A Review

Morphology of Intermetallics Tailoring Tensile Properties and Quality Index of a Eutectic Al–Si–Ni Alloy

Effect of Ni and Sr on the microstructure and tensile properties of the squeeze cast Al‐Si‐Cu alloy at elevated temperatures

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