Static and fatigue strength of a die-cast aluminium alloy under different feeding conditions

Avalle, Massimiliano; Belingardi, Giovanni; Cavatorta, Maria Pia

doi:10.1243/14644200260044742

Cited by 6 publications

(4 citation statements)

References 5 publications

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“…[12] The influence of the porosity on the fatigue behavior of Al-Si-based aluminum alloys has been investigated experimentally. [3,13] The porosity was observed to have the greatest propensity for acting as a crack initiation site, and the fatigue strength decreased when the size of the porosity increased. [3] Several investigators have examined the influences of defects on the mechanical properties in cast Al alloys.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Defects on Tensile Properties of Cast ADC12 Aluminum Alloy

Okayasu

Sakai

2015

Metall Mater Trans A

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To better understand the effects of cast defects on mechanical properties, cast aluminum alloys with various porosities were used. Porosity in the cast samples was created during the casting process, and to clearly identify the porosity effects on the mechanical properties, artificial defects (porosity-like tiny holes) were created mechanically. The tensile properties for the cast aluminum alloys appear to be attributed to the area fraction of the porosity on the fracture surface (namely, the defect rate, DR), although there were different trends because of the different stress concentrations: the ultimate tensile strength and 0.2 pct proof strength were linearly related to DR, while a non-linear correlation was detected for fracture strain. Even in Al alloys with small amounts of defects, significant reductions in the fracture strain were observed. These results were verified using tensile tests on specimens containing artificial defects. The effects of artificial defects on the tensile properties were further investigated using numerous tiny holes, created in several formations. The artificial defects (several small holes), lined up at perpendicular (90 deg) and 45 deg directions against the loading direction, made significant reductions in the tensile properties, even though only weak defect effects were observed for the 90 deg loading direction. No severe defect effects were obvious for the specimen with a tiny defect of /0.1 mm, because of the lower stress concentration, compared to the microstructural effects in the cast Al alloys: the grain boundaries and the second phases. Such phenomena were clarified using tensile tests on cast samples with differently sized microstructures. There were no clear defect effects on the yield strength as the defect amount was less than 10 pct, and microstructural effects were not detected either in this case. Failure characteristics during tensile loading were revealed directly by in-situ strain observations using high-speed cameras.

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Section: Introductionmentioning

confidence: 99%

The Effects of Defects on Tensile Properties of Cast ADC12 Aluminum Alloy

Okayasu

Sakai

2015

Metall Mater Trans A

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“…These studies show that fatigue fractures are mainly triggered by pores, especially in sandcast alloys [1][2][3][4][5]. The size of these pores varies between different samples, leading to a noticeable scatter in fatigue life when testing real components.…”

Section: Introductionmentioning

confidence: 96%

Fatigue variability in Al–Si cast alloys

Casellas

Pérez

Prado

2005

Materials Science and Engineering: A

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“…In a study by Avalle et al, it appeared that the casting defects made a significant reduction in the static and fatigue properties of die cast aluminium alloys. 3 To reduce the casting defects, high quality cast aluminium alloys have been produced using various casting technologies, such as vacuum casting, pore free casting, squeeze casting, semisolid forming, slow speed filling casting and continuous casting. [4][5][6][7][8][9] Although several casting techniques have been proposed, the mechanical properties of the resulting castings have not been always investigated.…”

Section: Introductionmentioning

confidence: 99%

Fatigue properties (S–Nand da/dN–ΔK) of cast aluminium alloys

Okayasu

Takasu

Niikura³

et al. 2013

International Journal of Cast Metals Research

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In this paper, the fatigue strengths of cast aluminium alloys have been examined using the S-N and da/dN-DK approaches on various cast samples having different microstructural characteristics. These were made by several different casting techniques, namely gravity casting, die casting and twin rolled continuous casting. Owing to the different microstructures, the fatigue properties varied. The S-N relations, e.g. the endurance limit, of the twin-rolled casting were apparently high compared to the other cast samples. The high fatigue strength was related to the high tensile strength and high ductility caused by the tiny spherical a-Al phase and fine eutectic structure. On the other hand, the low fatigue strength for the gravity and die cast samples was caused by the high stress concentration caused by the a-Al phase and needle-like eutectic silicon. Unlike the fatigue strength in the S-N approach, the da/dN-DK relationships for the twin rolled casting sample, i.e. the resistance to fatigue crack propagation, were low compared to the gravity casting and the die cast samples. Such a difference in the crack growth resistance was influenced by the crack growth characteristics. For example, for the gravity cast and the die cast samples, the crack growth occurs in the grain boundaries of the coarse a-Al phase and along the long eutectic silicon grains (zigzag crack path), which promotes a strong crack closure tendency, leading to high crack growth resistance. The difference in the fatigue strength determined from the S-N relation and da/dN-DK relation was interpreted by experimental and numerical examination of the stress-strain distribution.

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Static and fatigue strength of a die-cast aluminium alloy under different feeding conditions

Cited by 6 publications

References 5 publications

The Effects of Defects on Tensile Properties of Cast ADC12 Aluminum Alloy

The Effects of Defects on Tensile Properties of Cast ADC12 Aluminum Alloy

Fatigue variability in Al–Si cast alloys

Fatigue properties (S–Nand da/dN–ΔK) of cast aluminium alloys

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