scholarly journals Potential of High Compressive Ductility of Ultrafine Grained Copper Fabricated by Severe Plastic Deformation

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1503
Author(s):  
Mayu Asano ◽  
Motohiro Yuasa ◽  
Hiroyuki Miyamoto ◽  
Tatsuya Tanaka ◽  
Can Erdogan ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Void Formation ◽  
Rate Sensitivity ◽  
High Strength ◽  
Local Strain ◽  
Tensile Tests ◽  
Dislocation Slip ◽  
Shear Mode ◽  
Ultrafine Grained

Severe plastic deformation (SPD) can fabricate high-strength materials by forming an ultrafine grained (UFG) microstructure. Low elongation to failure of UFG materials in tensile tests, which has often been regarded as a measure of ductility of materials, has been attributed to low strain hardening of UFG structures where dislocation slip and its accumulation is very limited. In the present work, it is shown that the compressive extensibility of UFG materials can be comparable or potentially superior to that of annealed materials by using a parallel round-bar compression (PRBC) test which was designed for imposing an appropriate stress state preferable for high ductility using the shear mode. The high compressive extensibility of UFG materials can be a result of high accommodation of local strain incompatibility at non-equilibrium grain boundaries and a grain boundary-mediated deformation mechanism, which result in high damage tolerance against void formation and growth. Low strain rate sensitivity indicated that the superplastic viscous nature of deformation is not involved in the high compressive ductility of UFG materials using SPD.

scholarly journals On the origin of the extremely high strength of ultrafine-grained Al alloys produced by severe plastic deformation

2010 ◽  
Vol 63 (9) ◽  
pp. 949-952 ◽  
Author(s):  
R.Z. Valiev ◽  
N.A. Enikeev ◽  
M.Yu. Murashkin ◽  
V.U. Kazykhanov ◽  
X. Sauvage
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Al Alloys ◽  
Ultrafine Grained

THE PROPERTIES OF BULK ULTRAFINE-GRAINED METALS PROCESSED THROUGH THE APPLICATION OF SEVERE PLASTIC DEFORMATION

2012 ◽  
Vol 05 ◽  
pp. 299-306
Author(s):  
TERENCE G. LANGDON
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Elevated Temperatures ◽  
High Pressure Torsion ◽  
Superplastic Forming ◽  
High Strength ◽  
Basic Principles ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Processing Techniques

Processing through the application of severe plastic deformation (SPD) provides a very attractive tool for the production of bulk ultrafine-grained materials. These materials typically have grain sizes in the submicrometer or nanometer ranges and they exhibit high strength at ambient temperature and, if the ultrafine grains are reasonably stable at elevated temperatures, they have a potential for use in superplastic forming operations. Several procedures are now available for applying SPD to metal samples but the most promising are Equal-Channel Angular Pressing (ECAP) and High-Pressure Torsion (HPT). This paper examines the basic principles of ECAP and HPT and describes some of the properties that may be achieved using these processing techniques.

Influence of Severe Plastic Deformation on Mechanical Properties of an AA5024 Alloy

2016 ◽  
Vol 879 ◽  
pp. 1317-1322 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Yuzbekova ◽  
Tatiana Lebedkina ◽  
Mikhail Lebyodkin ◽  
Rustam Kaibyshev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Coarse Grained ◽  
Type B ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Elongation To Failure ◽  
Dislocation Strengthening

The paper reports on the effect of severe plastic deformation on mechanical properties of an Al-4.57Mg-0.35Mn-0.2Sc-0.09Zr (in wt. pct.) alloy processed by equal channel angular pressing followed by cold rolling (CR). The sheets of the 5024 alloy with coarse grained (CG) structure exhibited a yield stress (YS) near 410 MPa and an ultimate tensile strength (UTS) of 480 MPa, while the YS and UTS of this material with ultrafine-grained (UFG) structure increased to 530 and 560 MPa, respectively. On the other hand, the elongation to failure decreased by a factor of 2 and 4 after CR and CR following ECAP, respectively. It was shown that dislocation strengthening attributed to extensive CR plays a major role in achieving high strength of this alloy. Besides these macroscopic characteristics, jerky flow caused by the Portevin-Le Chatelier (PLC) instability of plastic deformation was examined. The formation of UFG structure results in a transition from mixed type A+B to pure type B PLC serrations. No such effect on the serrations type was observed after CR.

Influence of Annealing on the Structure and Mechanical Properties of Ultrafine-Grained Alloy Ti-6Al-7Nb, Processed by Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 943-948 ◽  
Author(s):  
Veronika Polyakova ◽  
Irina P. Semenova ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
Human Body ◽  
High Strength ◽  
Point Of View ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Strength And Ductility

This work is devoted to enhancement of strength and ductility of the Ti-6Al-7Nb ELI alloy, which is less harmful from medical point of view for human body in comparison to Ti-6Al-4V. It has been demonstrated that formation of an ultrafine-grained structure in the alloy with the help of equal-channel angular pressing in combination with heat and deformation treatments allows reaching high strength (UTS = 1400 MPa) and sufficient ductility (elongation 10 %).

scholarly journals Ultrafine-Grained High Strength Cu-Ni-Si Alloys

2017 ◽  
Vol 892 ◽  
pp. 64-69 ◽  
Author(s):  
Igor Altenberger ◽  
Hans Achim Kuhn ◽  
Mozhgan Gholami-Kermanshahi ◽  
Mansour Mhaede ◽  
Manfred Wollmann ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Copper Alloys ◽  
Pure Copper ◽  
High Strength ◽  
Solid Solution Hardening ◽  
Subsequent Aging ◽  
Ultrafine Grained ◽  
Wide Range

Ultrafine-grained (UFG) pure copper has been in the focus of materials scientists over the last two decades, however ultrafine-grained high-strength copper alloys have scarcely been processed or characterized so far industrially.In this contribution, UFG copper alloys, especially Cu-Ni-Si alloys, being well known as ideal materials for electromechanical connectors, springs and leadframes, are presented. Precipitation hardened Cu-Ni-Si alloys are a well established and technologically important class of materials for a wide range of applications where high strength and good conductivity are required. Yield strength and fatigue properties of metallic alloys can be significantly enhanced by severe plastic deformation methods. In contrast to other strengthening methods such as solid solution hardening, severe plastic deformation leads to a weaker decrease of electrical conductivity and is therefore a means of enhancing strength while maintaining acceptable conductivity for current bearing parts and components. Characterization of these materials after severe plastic deformation by swaging, wire drawing and subsequent aging was carried out using conductivity-, hardness-and tensile tests as well as highly-resolved microstructural characterization methods.The results reveal that UFG low alloyed copper alloys exhibit impressive combinations of properties such as strength, conductivity, high ductility as well as acceptable thermal stability at low and medium temperatures. By a subsequent aging treatment the severely plastically deformed microstructure of Cu-Ni-Si alloys can be further enhanced and thermal stability can profit from grain-boundary pinning by precipitated nanoscale nickel silicides.

Development of Complex Methods, Combining Thermal Treatment with Severe Plastic Deformation, for Processing of High-Strength Nanostructured Cu-1%Cr-0.7%Al Alloy

2006 ◽  
Vol 503-504 ◽  
pp. 515-520 ◽  
Author(s):  
Igor V. Alexandrov ◽  
V.V. Latysh ◽  
Sun Ig Hong ◽  
S.N. Faizova ◽  
V.M. Polovnikov
Keyword(s):  
Plastic Deformation ◽  
Thermal Treatment ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
High Strength ◽  
Al Alloy ◽  
Thermal Treatments ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Complex Methods

The current work presents new results of investigation of properties and structure of nanocrystalline and submicrocrystalline Cu-1%Cr-0.7%Al alloy. Two severe plastic deformation (SPD) techniques were applied to refine the structure: high pressure torsion and equal-channel angular pressing (ECAP). The first technique was applied to conduct preliminary studies of the alloy different thermal treatments as before SPD as well as after it. A new technological thermomechanical technique for processing of bulk billets of Cu-1%Cr-0.7%Al alloy possessing an ultrafine grained structure was developed on the basis of the obtained results. This technique comprises a combination of ECAP and other deformational processes with the thermal treatment. High values of the tensile strength and yield stress - 700 MPa and 16% accordingly – have been obtained as a result of such treatment, whereas these values after conventional treatment consisted 450 MPa and 20% respectively.

The Influence of Work Hardening, Internal Stresses, and Stress Relaxation on Ductility of Ultrafine Grained Materials Prepared by Severe Plastic Deformation

2009 ◽  
Vol 633-634 ◽  
pp. 263-272
Author(s):  
David G. Morris ◽  
Maria A. Muñoz-Morris ◽  
Ivan Gutierrez-Urrutia
Keyword(s):  
Plastic Deformation ◽  
Stress Relaxation ◽  
Severe Plastic Deformation ◽  
Work Hardening ◽  
Deformation Behaviour ◽  
High Strength ◽  
Internal Stresses ◽  
Fracture Ductility ◽  
Ultrafine Grained ◽  
Ultrafine Grained Materials

Ultrafine grained materials prepared by methods of severe plastic deformation appear to show good ductility for their high strength. To a large extent this ductility enhancement, for the given strength, is shown to correspond to the fracture ductility and not the uniform ductility at maximum stress. The improved fracture ductility is often due to the refinement or removal of the coarse defects that act as sites for failure nucleation. The low work hardening rate inherent to the very fine microstructures produced by severe plastic deformation essentially condemns such materials to very low uniform ductility. Stress relaxation occurring during unloading after processing, and changes of internal stresses during reloading for mechanical testing, appear to play a significant role in determining deformation behaviour near the onset of plastic flow, and this can affect the measured uniform strain.

Ultrafine Grained Low Carbon Steels Processed by Severe Plastic Deformation

2008 ◽  
Vol 584-586 ◽  
pp. 623-630 ◽  
Author(s):  
Sergey V. Dobatkin ◽  
P.D. Odessky ◽  
Svetlana V. Shagalina
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
High Strength ◽  
Carbon Steels ◽  
Low Alloy Steels ◽  
Low Carbon ◽  
Low Carbon Steels ◽  
Ultrafine Grained

The structure, mechanical and functional properties of ultrafine-grained low-carbon steels have been studied after severe plastic deformation (SPD) by high pressure torsion (HPT) and equalchannel angular pressing (ECAP). It is revealed that HPT of low carbon steels at a temperature below 0.3 Tm leads to the formation of nanocrystalline structure with a grain size of <100 nm or a mixture of oriented substructure and nanograins. ECAP under similar conditions leads to the formation of submicrocrystalline structure with a grain size of 200-300 nm. The initial martensitic state compared with the initial ferritic-pearlitic state of the low-carbon steels results in formation of finer structure after SPD and less intense grain growth upon heating, i.e., results in a higher thermal stability. Low-carbon low-alloy steels after ECAP are characterized by high strength (UTS > 1000 MPa) and plasticity (EL = 10-15%). The high-strength state after ECAP is retained upon tensile test testing up to a temperature of 500°C. The submicrocrystalline low-carbon steels after ECAP processing and subsequent heating is characterized by an increased impact toughness at test temperatures down to -40°C.

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