Influence of fine-grained structure and superplastic deformation on the strength of aluminium alloys

Rabinovich, M. Kh.; Маркушев, М. В.

doi:10.1007/bf00355893

Cited by 23 publications

(8 citation statements)

References 11 publications

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“…Also, length of a crack path in its growth is smaller in fine‐grained alloys 8,10 which leads to a decrease in amount of energy required for crack propagation. The decrease of crack length is the consequence of the change in the fracture mode, where the crack path is more tortuous during fatigue crack growth in coarse‐grained materials . Similar results for straight crack path after ECAP are reported in…”

Section: Resultssupporting

confidence: 80%

“…Nature of difference in crack growth behaviour in fine‐grained and coarse‐grained materials can be summarized in parameters affecting fatigue crack propagation energy. The growth of cracks requires the expenditure of energy (E T ) in terms of energy expended for plastic deformation at the crack tip (E d ), which is related to linear size of plastic deformation zone, energy expended for formation of free surfaces (E s ), which is related to real crack length and energy expended for relaxation (E r ):

E_{T} = E_{d} + E_{s} - E_{r}

…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, energy of the unloading cycle is not enough for reverse slip of dislocations, and the accumulation of fatigue damage is larger than that for the coarse‐grained specimens . Also, this is the cause for formation of pile‐ups and nucleation of cracks, which increases the propagation rate of long fatigue cracks . Furthermore, fine‐grained materials have experienced smaller blunting and fatigue crack closure, which also decrease fatigue crack growth resistance .…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, fine‐grained materials have experienced smaller blunting and fatigue crack closure, which also decrease fatigue crack growth resistance . Also, plastic deformation of a fine‐grained alloy needs a higher external stresses, which lead to a higher relaxation energy …”

Section: Resultsmentioning

confidence: 99%

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Fatigue crack growth resistance of 7075 Al alloy after equal channel angular pressing

Ghalehbandi

Arezoodar

Hosseini‐Toudeshky

2016

Fatigue Fract Eng Mat Struct

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A B S T R A C T This work presents experimental results on effects of severe plastic deformation (SPD) and subsequent natural ageing on tensile mechanical properties and fatigue crack growth resistance of fine-grained 7075 Al alloy. The alloy was subjected to equal channel angular pressing (ECAP) after solution treatment. Fatigue crack propagation tests were conducted in room condition, at load ratio R = 0.1 and different load ranges on small disk shaped compact tension specimens. Fatigue fracture surface is also investigated using scanning electron microscopy observations and showed more ductile fatigue crack growth in the unECAPed specimen. Despite the increased tensile strength after ECAP, the ductility that controls low-cycle fatigue behaviour has decreased. It is found that ECAP has resulted in a remarkable change in Paris regime parameters and a significant increase in fatigue crack growth rate. The decrease in fatigue crack growth resistance and ΔK c after ECAP can be attributed to the decrease in alloy's ductility.Keywords 7075 Al alloy; ageing; ECAP; fatigue crack growth. N O M E N C L A T U R Ea = Crack length B = Specimen thickness C = Paris law parameter E T = Total energy expended for fatigue crack growth E d = Energy expended for plastic deformation at the crack tip E s = Energy expended for formation of free surfaces E r = Energy expended for relaxation m = Paris law parameter N = Number of cycles R = Cyclic load ratio W = Specimen width ΔK = Stress intensity factor range ΔK c = Stress intensity factor range for catastrophic failure ΔP = Applied load range I N T R O D U C T I O NAluminium alloys are widely used in engineering applications. There is, nevertheless, much significance to improve mechanical properties of the alloys using engineering processes. Although mechanical properties of all crystalline materials are determined by several factors, the average grain size plays a very significant and often a dominant role. In order to decrease the grain size of a material using metal-working procedures, it is necessary to impose an exceptionally high strain in order to introduce a high density of dislocations subsequently rearranged to form an array of grain boundaries. In practice, because of the limitations of Correspondence: A. Fallahi.

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Section: Resultssupporting

confidence: 80%

E_{T} = E_{d} + E_{s} - E_{r}

…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Fatigue crack growth resistance of 7075 Al alloy after equal channel angular pressing

Ghalehbandi

Arezoodar

Hosseini‐Toudeshky

2016

Fatigue Fract Eng Mat Struct

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“…Much research focuses of superplasticity of fine-grained and ultrafine-grained (UFG) Al-Mg alloys doped with REE and PM [43,. The literature review shows that UFG Al-Mg-(Sc,Zr) alloys, including industrial alloys [88,99,106,108,109], demonstrate the highest superplasticity characteristics. High superplasticity characteristics of UFG Al-Mg-(Sc,Zr) alloys system from high stability of their UFG microstructure at elevated deformation temperatures.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sc:Zr Ratio on Superplastic Behavior of Ultrafine-grained Al-6%Mg-Sc-Zr Alloys

Чувильдеев¹,

Gryaznov²,

Shotin³

et al. 2022

Preprint

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Al-6%Mg-Sc-Zr alloys with the total ratio of Sc + Zr = 0.32 wt.% make up the target of this research. The content of scandium and zirconium varied with an increment of 0.02%. The alloys were produced by induction casting. Their ultrafine-grained (UFG) microstructure was formed with Equal Channel Angular Pressing (ECAP). Such cast alloys have a homogeneous macrostructure formed by small equiaxed grains in the central part of the ingot and columnar crystals along the edges of the cross section. After ECAP, the average grain size in the alloy specimens is 0.5–1 µm. The average grain size does not depend on the ratio of Sc and Zr in these alloys. Superplasticity tests were performed at temperatures ranging from 300 to 500 °C and at a strain rate varying between 3.3·10-3 and 3.3·10-1 s-1. UFG Al-6%Mg-0.20%Sc-0.12%Zr and Al-6%Mg-0.18%Sc-0.14%Zr alloys exhibit the highest superplasticity. It was suggested that changes in Sc:Zr ratio affect spatial distribution and composition of the following precipitating particles: Al3Sc, Al3Zr, Al3(ScxZr1-x). An increase in Zr concentration is shown to reduce the susceptibility of UFG alloys to cavitation fracture.

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Strength of Submicrocrystalline Severely Deformed Commercial Aluminum Alloys

Маркушев¹,

Murashkin²

2002

Ultrafine Grained Materials II

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Influence of fine-grained structure and superplastic deformation on the strength of aluminium alloys

Cited by 23 publications

References 11 publications

Fatigue crack growth resistance of 7075 Al alloy after equal channel angular pressing

Fatigue crack growth resistance of 7075 Al alloy after equal channel angular pressing

Effect of Sc:Zr Ratio on Superplastic Behavior of Ultrafine-grained Al-6%Mg-Sc-Zr Alloys

Strength of Submicrocrystalline Severely Deformed Commercial Aluminum Alloys

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