Aging Behaviour of Aluminium Alloys after Severe Plastic Deformation

2006 ◽  
Vol 519-521 ◽  
pp. 1485-1492 ◽  
Author(s):  
Z. Horita
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Strength ◽  
Age Hardening ◽  
Precipitation Process ◽  
Al Alloy ◽  
Metallic Materials ◽  
Aging Behavior ◽  
Angular Pressing ◽  
Transmission Electron

The process of severe plastic deformation (SPD) makes it possible to reduce the grain size to the submicrometer or nanometer range in many metallic materials. When the SPD process is applied to age hardenable alloys, it may also be possible to control aging behavior. In this study, a technique of equal-channel angular pressing (ECAP) is used as an SPD process and aging behavior is examined on the three selected Al alloy systems such as Al-Ag, Al-Mg-Si and Al-Si-Ge. The microstructures are observed using transmission electron microscopy and the mechanical properties including hardness are measured. It is shown that the SPD process introduces unusual phenomena in the precipitation process and there should be a potential for enhancement of strength over the conventional age-hardening process or for improvement of ductility while keeping the high strength.

Equal Channel Angular Pressing of Al Alloy AA2219

2009 ◽  
Vol 67 ◽  
pp. 53-58
Author(s):  
V. Anil Kumar ◽  
M.K. Karthikeyan ◽  
Rohit Kumar Gupta ◽  
P. Ramkumar ◽  
P.P. Sinha
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Equal Channel Angular Pressing ◽  
High Strength ◽  
Dark Field ◽  
Grain Structure ◽  
Al Alloy ◽  
Angular Pressing

Severe plastic deformation processes (SPD) are gaining importance as advanced materials processing techniques and hold immense potential in obtaining ultra fine-grained high strength materials. Among the SPD techniques, Equal channel angular pressing (ECAP) has its own merits to produce materials with ultra fine grains in bulk with better mechanical properties. The material deforms with high level of plastic strain inside the channel resulting in grain refinement of the output material with improvement in mechanical properties. A very viable die configuration was conceptualized and die was made with 1200 channel angle. Processing of 25 mm dia. of Al alloy AA2219 at room temperature was successfully carried out and grain refinement was observed. The mechanism of grain refinement has been studied using optical and transmission electron microscopy (TEM). It was observed that low energy dislocation structure (LEDS) forms concurrently with sub-grain structure due to dislocation rearrangements, which provide stability to the evolving sub-grain structure. Dislocation mobility is hindered by the presence of precipitates and / or intermetallic dispersoids present in the matrix and results in presence of dislocations in grain interiors. The pile up of dislocations at intermetallic dispersoids was confirmed from the dark field TEM micrographs. Present paper describes the experimental procedure and followed to attain severe plastic deformation through ECAP. Increase in hardness as well as refinement in the grain size after 5-passes have been discussed in light of extensive optical and TEM. The mechanisms of grain refinement to achieve nano-grained structure and strengthening accrued from the grain refinement through ECAP has been discussed.

scholarly journals Precipitation and Mechanical Properties of Supersaturated Al-Zn-Mg Alloys Processed by Severe Plastic Deformation

2006 ◽  
Vol 519-521 ◽  
pp. 835-840 ◽  
Author(s):  
I. Schiller ◽  
Jenő Gubicza ◽  
Zsolt Kovács ◽  
Nguyen Q. Chinh ◽  
Judit Illy
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Profile Analysis ◽  
Precipitation Process ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
Characteristic Parameters ◽  
Diffraction Line Profile ◽  
Angular Pressing ◽  
Transmission Electron

Supersaturated Al-4.8Zn-1.2Mg-0.14Zr and Al-5.7Zn-1.9Mg-0.35Cu (wt.%) alloys were processed by Equal-Channel Angular Pressing (ECAP) at 200°C. The crystallite size distribution and the characteristic parameters of the dislocation structure of both Al matrix and precipitates were determined by X-ray diffraction line profile analysis, which has been complemented by transmission electron microscopy (TEM) observations. The results show that severe plastic deformation promotes the precipitation process and consequently has a strong influence on the strength of these alloys.

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.

scholarly journals Hierarchical nanostructured aluminum alloy with ultrahigh strength and large plasticity

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Ge Wu ◽  
Chang Liu ◽  
Ligang Sun ◽  
Qing Wang ◽  
Baoan Sun ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Structural Design ◽  
Flow Behavior ◽  
High Strength ◽  
Al Alloy ◽  
High Ductility ◽  
Metallic Materials ◽  
Trade Off ◽  
Ultrahigh Strength ◽  
Continuous Generation

Abstract High strength and high ductility are often mutually exclusive properties for structural metallic materials. This is particularly important for aluminum (Al)-based alloys which are widely commercially employed. Here, we introduce a hierarchical nanostructured Al alloy with a structure of Al nanograins surrounded by nano-sized metallic glass (MG) shells. It achieves an ultrahigh yield strength of 1.2 GPa in tension (1.7 GPa in compression) along with 15% plasticity in tension (over 70% in compression). The nano-sized MG phase facilitates such ultrahigh strength by impeding dislocation gliding from one nanograin to another, while continuous generation-movement-annihilation of dislocations in the Al nanograins and the flow behavior of the nano-sized MG phase result in increased plasticity. This plastic deformation mechanism is also an efficient way to decrease grain size to sub-10 nm size for low melting temperature metals like Al, making this structural design one solution to the strength-plasticity trade-off.

scholarly journals Determination of microstructural changes by severely plastically deformed copper-aluminum alloy: Optical study

2014 ◽  
Vol 50 (1) ◽  
pp. 61-68 ◽  
Author(s):  
N. Romcevic ◽  
M. Gilic ◽  
I. Anzel ◽  
R. Rudolf ◽  
M. Mitric ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Structural Characteristics ◽  
Al Alloy ◽  
Local Structures ◽  
Angular Pressing ◽  
Aluminum Solid Solution ◽  
Oxide Particles ◽  
Copper Aluminum ◽  
Nanosized Oxide

Our work deals with the problem of producing a complex metal-ceramic composite using the processes of internal oxidation (IO) and severe plastic deformation. For this purpose, Cu-Al alloy with 0.4wt.% of Al was used. IO of sample serves in the first step of the processing as a means for attaining a fine dispersion of nanosized oxide particles in the metal matrix. Production technology continues with repeated application of severe plastic deformation (SPD) of the resulting metalmatrix composite to produce the bulk nanoscaled structural material. SPD was carried out with equal channel angular pressing (ECAP), which allowed that the material could be subjected to an intense plastic strain through simple shear. Microstructural characteristics of one phase and multiphase material was studied on internally oxidized Cu with 0.4wt.% of Al sample composed of one phase copper-aluminum solid solution in the core and fine dispersed oxide particles in the same matrix in the mantle region. In this manner AFM, X-ray diffraction and Raman spectroscopy were used. Local structures in plastically deformed samples reflect presence of Cu, CuO, Cu2O, Cu4O3 or Al2O3 structural characteristics, depending on type of sample.

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.

scholarly journals Precipitation Microstructure of Ultrafine-Grained Al-Zn-Mg Alloys Processed by Severe Plastic Deformation

2007 ◽  
Vol 537-538 ◽  
pp. 169-176 ◽  
Author(s):  
Jenő Gubicza ◽  
I. Schiller ◽  
Nguyen Q. Chinh ◽  
Judit Illy
Keyword(s):  
Profile Analysis ◽  
High Strength ◽  
Precipitation Process ◽  
Line Profile Analysis ◽  
X Ray Diffraction ◽  
Diffraction Line Profile ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Precipitation Microstructure

Supersaturated Al-4.8Zn-1.2Mg-0.14Zr and Al-5.7Zn-1.9Mg-0.35Cu (wt.%) alloys were processed by Equal-Channel Angular Pressing (ECAP) at 200°C. The crystallite size distribution and the characteristic parameters of the dislocation structure of both Al matrix and precipitates were determined by X-ray diffraction line profile analysis, which has been complemented by transmission electron microscopy (TEM) observations. Results of these investigations show that the bulk ultrafine-grained microstructure with high dislocation density produced by ECAP has strong influence on the precipitation process, resulting in high strength in both alloys.

Properties of Metallic Materials after Surface Self Nano-Crystallization

2014 ◽  
Vol 941-944 ◽  
pp. 416-420 ◽  
Author(s):  
Guang Yu Pei ◽  
Dong Li ◽  
Kai Bin Li
Keyword(s):  
Plastic Deformation ◽  
Wear Resistance ◽  
Corrosion Resistance ◽  
Surface Layer ◽  
Severe Plastic Deformation ◽  
Compressive Stress ◽  
High Strength ◽  
Metallic Materials ◽  
Diffusion Property ◽  
Surface Nanocrystallization

Surface Self-nanocrystallization (SSNC) can produce nanometer grains (10~50μm depth) in the surface layer of metallic materials. And high strength, residual compressive stress as well as a mass of defects attributed to grain refinement and severe plastic deformation, greatly improve their surface properties, such as strength, wear resistance, diffusion property, fatigue performance and corrosion resistance. Now some methods have been confirmed which could realize surface nanocrystallization. This paper reviews the study of surface nanocrystallization and simply summarizes changes in their performance based on surface layer microstructure of metallic materials.

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