Fatigue design factors for ECAPed materials

Djavanroodi, F.; Ebrahimi, Mahmoud; Rajabifar, Bahram; Akramizadeh, S.

doi:10.1016/j.msea.2010.09.080

Cited by 50 publications

(20 citation statements)

References 24 publications

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“…Note that such a trend is the same as that observed for unalloyed pure Al [27][28][29][30] or 6061 with higher Si content [2]. In contrast, the curve of the new alloy shows clear discontinuity; N f significantly increases at  a between 90…”

Section: S-n Behavior Analysissupporting

confidence: 69%

Effect of additional magnesium on mechanical and high-cycle fatigue properties of 6061-T6 alloy

Takahashi¹,

Shikama²,

Nakamichi³

et al. 2015

Materials Science and Engineering: A

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Abstract:The effect of additional solute magnesium (Mg) on mechanical and high-cycle-fatigue properties of 6061-T6 aluminum alloy is investigated in detail. By adding 0.5% and 0.8% Mg to the 6061-T6 alloy with a normal stoichiometric Mg 2 Si composition (base alloy), the alloy exhibits eminent strain-aging characteristics demonstrated by the emergence of serrated flow, the negative 2 strain-rate-sensitivity and relatively weakened temperature dependency of flow stress. The Mg-added new alloy also shows higher work-hardening rate than the base alloy particularly at initial flow regime and at lower strain rate. The S-N curve of the new alloy shows a clear fatigue limit which is absent in the base alloy. The fatigue limit of the new alloy is shown to be controlled by the threshold against small crack growth. Moreover, the new alloy clearly exhibits a coaxing phenomenon (time-dependent strengthening) which is absent in the base alloy. The coaxing effect is attributed to the existence of a small quasi-non-propagating crack whose growth resistance gradually increases during stress amplitude step-ups.

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Section: S-n Behavior Analysissupporting

confidence: 69%

Effect of additional magnesium on mechanical and high-cycle fatigue properties of 6061-T6 alloy

Takahashi¹,

Shikama²,

Nakamichi³

et al. 2015

Materials Science and Engineering: A

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show abstract

“…Higher strength and microhardness in ultra-ne and nanostructured grained metals, especially near the surface regions which are crack nucleation sites, cause greater resistance to crack initiation by prevention of plastic deformation at the beginning of fatigue testing. This process increases the incubation period for crack nucleation and the total fatigue life of ECARed copper at high stresses [6,17]. The dislocation density within the grains could increase after the ECAR process.…”

Section: Microhardness and Tensile Test Resultsmentioning

confidence: 99%

“…Thus, in a highstress amplitude, strength is dominant and improves the material's resistance to crack initiation, whereas in a strain-controlled test, ductility determines the number of cycles to fracture controlled by crack propagation [5,6]. Then, it was suggested that by producing bi-modal grain structures with small and large grains, a combination of strength and ductility and improved fatigue properties may be achieved.…”

Section: Microhardness and Tensile Test Resultsmentioning

confidence: 99%

“…The resistance to crack initiation increases with higher strength while resistance to crack propagation requires ductility. A combination of high strength and good ductility in the nanostructured materials enhances their fatigue properties [2,6]. Several studies have explored the grainsize e ects on cyclic deformation of Ultra-Fine Grain (UFG) materials produced by ECAP.…”

Section: Introductionmentioning

confidence: 99%

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Fatigue behavior of nano-grained pure copper processed by equal channel angular rolling

Habibi¹,

Ketabchi²,

Eskandarzadeh³

2017

Scientia Iranica

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Abstract. The equal channel angular rolling process was successfully performed on commercial pure copper. After 4 passes of this process, grains with a diameter of about 70-500 nm were formed. The fatigue test results showed that the ultra-ne grained copper represents a longer lifetime under stress-controlled fatigue. To clarify the formation process of surface damage, morphological changes in the fractured surface were monitored by scanning electron microscopy.

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“…Recently, several methods of severe plastic deformation (SPD) were developed to process bulk nanostructured materials with a grain size from 20 to 200nm depending on a number of factors [5][6][7][8]. Equal channel angular pressing (ECAP) is considered the most popular among the various SPD processes.…”

Section: Introductionmentioning

confidence: 99%

Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

Abushgair¹

2015

AIP Conference Proceedings

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Abstract. In this work we were interested in doing simulation using finite elements analysis (FEA) to study the equal channel angular pressing process (ECAP), which is currently one of the most popular methods of severe plastic deformation Processes (SPD) . for fabricating Ultra-Fine Grained (UFG) materials, because it allows very high strains to be imposed leading to extreme work hardening and microstructural refinement. The main object of this study is to establish the influence of main parameters which effect ECAP process which are magnitude of the die angle and the friction coefficient. The angle studied between (90-135 º ) degree, and magnitude of the friction coefficient μ between (0.12-0.6), and number of pass. The samples were made from aluminum alloy at room temperature with (15X 15) mm cross section and 150 mm length. The simulation result shows that normal elastic strain, shears elastic strain, and max. shear elastic strain increased , when changing the angle from 90 o to 100 o . and decrease between the angle 110 o to 135 o .Also the total deformation increased when we change die angle from 90 o to 135 o . By studding the friction effect on the die and sample we noted that increasing the friction coefficient from 0.12 to 0.6, normal elastic strain, and shear elastic strain increased and increasing the friction coefficient from 0.1 to 0.6 decrease the normal and shear stress.

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Fatigue design factors for ECAPed materials

Cited by 50 publications

References 24 publications

Effect of additional magnesium on mechanical and high-cycle fatigue properties of 6061-T6 alloy

Effect of additional magnesium on mechanical and high-cycle fatigue properties of 6061-T6 alloy

Fatigue behavior of nano-grained pure copper processed by equal channel angular rolling

Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

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