Fatigue limit prediction of A356-T6 cast aluminum alloys with different defect sizes sampled from an actual large-scale component

Purpose The purpose of this paper is the proposal of fatigue-life-prediction curve for cast aluminum alloy A356-T6 with different casting defect sizes. Design/methodology/approach Four kinds of A356-T6 fatigue specimens were sampled from the actual large-scale cast component, where the cooling rates were different. In addition, three kinds of A356 were casted under different casting conditions to simulate different defect sizes in the actual component. Subsequently, rotating bending fatigue tests were conducted using those samples. The maximum sizes of casting defects were quantitatively evaluated through microstructural observation and extreme value statistics. The fatigue limits of all samples were predicted using hardness and defect sizes based on modified Murakami’s equation. Findings The modified equation for fatigue limit prediction in A356-T6 was proposed. Fatigue limits were successfully predicted using the proposed equation. Originality/value Fatigue limit prediction method using hardness and maximum defect size was limited to steels. This paper proposed the modified method for A356-T6 aluminum alloy with lower elastic modulus. The method was valid for A356-T6 with different defect sizes.

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Fatigue Limit Prediction of Large Scale Cast Aluminum Alloy A356

Procedia Materials Science ◽

10.1016/j.mspro.2014.06.150 ◽

2014 ◽

Vol 3 ◽

pp. 924-929 ◽

Cited By ~ 10

Author(s):

Akiko Tajiri ◽

Taishi Nozaki ◽

Yoshihiko Uematsu ◽

Toshifumi Kakiuchi ◽

Masaki Nakajima ◽

...

Keyword(s):

Aluminum Alloy ◽

Fatigue Limit ◽

Large Scale ◽

Cast Aluminum Alloy ◽

Cast Aluminum

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Large Scale Fatigue Simulation of Cast Aluminum Alloy

The Proceedings of the Materials and Mechanics Conference ◽

10.1299/jsmemm.2018.ps19 ◽

2018 ◽

Vol 2018 (0) ◽

pp. PS19

Author(s):

Miwako SAKURAI ◽

Masaki TERANISHI ◽

Osamu KUWAZURU ◽

Masakazu KOBAYASHI ◽

Hiroyuki TODA

Keyword(s):

Aluminum Alloy ◽

Large Scale ◽

Cast Aluminum Alloy ◽

Cast Aluminum

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Improvement of Fatigue Properties in a Cast Aluminum Alloy by Roller Burnishing and Friction Stir Processing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.891-892.662 ◽

2014 ◽

Vol 891-892 ◽

pp. 662-667 ◽

Cited By ~ 2

Author(s):

Yuki Nakamura ◽

Masaki Nakajima ◽

Hiroaki Masuda ◽

Toshifumi Kakiuchi ◽

Yoshihiko Uematsu

Keyword(s):

Residual Stress ◽

Aluminum Alloy ◽

Friction Stir Processing ◽

Compressive Residual Stress ◽

Fatigue Tests ◽

Fatigue Properties ◽

Cast Aluminum Alloy ◽

Cast Aluminum ◽

Bending Fatigue ◽

Friction Stir

Roller burnishing (RB) and friction stir processing (FSP) were applied to a cast aluminum alloy, AC4CH-T6 (equivalent to A356-T6), to improve the fatigue properties. In roller burnished specimens, Vickers hardness was increased until the depth of 60μm compared with that of the as-cast specimens, resulting in work-hardening by RB. The compressive residual stress on the surface of the roller burnished specimens was also increased from 35MPa to 132MPa. In order to investigate the effect of RB on the fatigue properties, rotary bending fatigue tests have been performed using the roller burnished and the as-cast specimens. The roller burnished specimens exhibited higher fatigue strength than the untreated specimens. It is due to the increase in hardness and compressive residual stress by RB. In addition, plane bending fatigue tests have been performed using the friction stir processed and untreated specimens. Fatigue strengths of the friction stir processed specimens were highly improved compared with untreated specimens as the results of the elimination of casting defects by FSP. However, the crack growth rates of the friction stir processed specimens were faster than those of untreated specimens. It is due to the softening of the material by heat input during the FSP.

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Fatigue Behavior of A356 Cast Aluminum Alloy Microstructurally Modified by Friction Stir Processing under Low Strain Rate Condition

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.525-526.169 ◽

2012 ◽

Vol 525-526 ◽

pp. 169-172

Author(s):

Toshifumi Kakiuchi ◽

Yoshihiko Uematsu ◽

Yasunari Tozaki

Keyword(s):

Aluminum Alloy ◽

Strain Rate ◽

Friction Stir Processing ◽

Fatigue Behavior ◽

Fatigue Tests ◽

Cast Aluminum Alloy ◽

Cast Aluminum ◽

Rate Condition ◽

Friction Stir ◽

Strain Rate Condition

The fatigue behavior of cast aluminum alloy, A356-T6, microstructurally modified by the friction stir processing (FSP) was investigated. The FSP conditions were set to be the tool rotational speed of 500 rpm and traveling speed of 200 mm/min, in which the strain rate was relatively low. Plane bending fatigue tests have been performed using the as-cast and friction stir processed (FSPed) specimens. Fatigue strengths in the finite life region and the fatigue limit of the FSPed specimens were highly improved compared with the as-cast ones resulting from the elimination of casting defects by the FSP. However, the crack growth rates of the FSPed specimens were faster than those of the as-cast ones due to the softening of the material by heat input during the FSP. The effects of FSP with low stain rate were discussed based on the microstructural consideration.

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