Effect of porosity on the tensile properties of low ductility aluminum alloys

Mugica, Gustavo W.; Tovio, Daniel O.; Cuyás, Julio César; González, Aulio César

doi:10.1590/s1516-14392004000200002

Cited by 43 publications

(20 citation statements)

References 10 publications

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“…The reason for this is not clear at the moment, but this could be affected by the complicated defect characteristics, e.g., pore shape, location, and size ( Figures 5 and 6(b)). In the previous work, a similar relationship between tensile strength (r UTS and r 0.2 ) and porosity in the proximity of the fracture in aluminum alloys was reported, although the evaluation was only conducted at low porosity rates of less than 3 pct; [7] moreover, Nakata et al [20] have reported the effect of cast defect (cold flake) on the tensile properties, and the tensile strength is relatively scattered. This would be attributed to the complicated structure of cold flake.…”

Section: Resultssupporting

confidence: 52%

“…There was a strong correlation between the porosity and mechanical properties of the cast Al alloys, in which the parameter of global volumetric porosity was used. [7] In the study by Zhao et al, [8] the tensile properties of Al-Si-Cu cast plate samples were found to be directly affected by porosity. The effects of porosity on mechanical properties have been investigated by several researchers (e.g., [9] ).…”

Section: Introductionmentioning

confidence: 98%

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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: Resultssupporting

confidence: 52%

Section: Introductionmentioning

confidence: 98%

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

Okayasu

Sakai

2015

Metall Mater Trans A

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“…The reason that such high mechanical strengths were obtained even though the relative density of the recycled materials was lower than 98% is discussed here. Mugica et al (2004) presented the relationship between the porosity and tensile properties in a cast Al-Si alloy whose chemical composition differed slightly from AC4CH, reporting that the yield strength (0.2% proof stress) and tensile strength were insensitive to varying porosity in the range of volumetric total porosity lower than 3%; even when a porosity of about 3% was included, the yield strength differed little from that in the case of a porosity lower than 0.1% and the tensile strength decreased by only about 20%. Hence, the high mechanical strengths of the recycled materials observed in the present study were a consequence of an increase in the strengths by grain and Si phase refinements as the result of the severe cold working, which exceeded the slight decline in the strengths depending on the porosity.…”

Section: Discussionmentioning

confidence: 99%

Solid-state recycling of aluminium alloy swarf through cold profile extrusion and cold rolling

Chiba¹,

Nakamura²,

Kuroda³

2011

Journal of Materials Processing Technology

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“…Consider the two extreme porosity samples of the present study from supported by the work of Yan et al, [32] which showed that an increase in the porosity from 1 to 5 pct in PM Ti-6Al-4V alloy does not significantly change the tensile strength properties. Mugica et al [33] in their study of an Al alloy, however, have shown that the degradation of tensile strength properties is directly related to volume fraction of porosity on the fracture surface, which is usually higher than the global volume fraction. In the present study, although the size of the extreme-sized pore varies from sample to sample, the average pore volume fraction at any cross section remained nearly the same.…”

Section: A Effect Of Porosity On Strengthmentioning

confidence: 98%

The Nature of Tensile Ductility as Controlled by Extreme-Sized Pores in Powder Metallurgy Ti-6Al-4V Alloy

Kumar

Chandran

Cao

et al. 2016

Metall Mater Trans A

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Tensile properties of Ti-6Al-4V titanium alloy, sintered by a new process (sintering, phase transformation, and dehydrogenation of titanium hydride compacts, termed HSPT process), were investigated to determine how the sintering pores influence the tensile strength and ductility. It was found that the ductility in the sintered alloy is severely affected by the size of the largest pore, referred here as extreme-sized pore, even when the average volume fraction of porosity is nearly constant between a large number of samples. It is shown that the rapid decrease in ductility, with an increase in the extreme pore size, is caused by strain localization around the extreme-sized pore and early crack initiation. This crack initiation leads to fracture of the plane containing the pore thereby limiting the extent of uniform plastic strain that can be attained before fracture. Interestingly, the strength properties are, however, found to be independent of the size of the extreme-sized pore. The results are explained on the basis of stress concentration and strain localization around the extreme-sized pores. The work also reveals that if the extreme-sized pores are eliminated, PM Ti-6Al-4V alloy with high strength (~1100 MPa) and good ductility (~12 pct), which is easily comparable to a wrought Ti-6Al-4V alloy, can be achieved even at oxygen levels up to 0.4 wt pct.

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Effect of porosity on the tensile properties of low ductility aluminum alloys

Cited by 43 publications

References 10 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

Solid-state recycling of aluminium alloy swarf through cold profile extrusion and cold rolling

The Nature of Tensile Ductility as Controlled by Extreme-Sized Pores in Powder Metallurgy Ti-6Al-4V Alloy

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