Effect of Severe Plastic Deformation on the Structure and Properties of the Aluminum Alloy System Al-Cu-Mg

2019 ◽  
Vol 822 ◽  
pp. 94-100
Author(s):  
Olga V. Paitova ◽  
Elena V. Bobruk ◽  
Svetlana Shasherina ◽  
Bu Fan Zhang
Keyword(s):  
Room Temperature ◽  
High Pressure Torsion ◽  
Natural Aging ◽  
Alloy System ◽  
Coarse Grained ◽  
Structural Elements ◽  
Structure And Properties ◽  
Transmission Electron ◽  
Temperature Standard ◽  
Local Shift

The structure and properties of discs from cast coarse-grained D16 alloy have been investigated with the help of optical metallography and transmission electron microscopy, after the traditional heat treatment (HT) modes or subjected to high pressure torsion (HPT) under pressure in 6 GPa at room temperature. Standard HT modes included: Т4 (hardening 495°С + natural aging at room temperature for 5 days) and Т6 (hardening 495°С + artificial aging at 185°С for 10 hours). It is shown that after HT of alloy D16 according to modes T6 and Т4, the sizes of the structural elements, compared with the original, decreased by about 4,8 times and the microhardness increased by 1,6 times. It is shown that after one or ten rotates of HPT in D16 alloy the sizes of structural elements, in comparison with initial, decreased by 393 and 899 times, and microhardness increased by 2,4 and 2,9 times, respectively. Detection of hardening hard, brittle and high-alloy copper γ2- phases (Cu9Al4) indicates the passage in the HPT process of the decomposition of a supersaturated solid solution (dynamic aging) in the planes of a local shift.

scholarly journals Особенности упрочнения структурированного интенсивной пластической деформацией сплава Al-Cu-Zr

2021 ◽  
Vol 63 (10) ◽  
pp. 1572
Author(s):  
Т.С. Орлова ◽  
Д.И. Садыков ◽  
М.Ю. Мурашкин ◽  
В.У. Казыханов ◽  
Н.А. Еникеев
Keyword(s):  
High Pressure Torsion ◽  
High Strength ◽  
Coarse Grained ◽  
X Ray Diffraction ◽  
Microstructural Parameters ◽  
Transmission Electron ◽  
Ultrafine Grained ◽  
Preliminary Annealing ◽  
Coarse Grained State ◽  
Additional Hardening

The effect of small additions of copper on the microstructure and physic-mechanical properties of an ultrafine-grained Al-1.47Cu-0.34Zr (wt%) alloy structured by high pressure torsion after preliminary annealing at 375 °C for 140 h has been studied. As a result of processing, high values of strength characteristics (conditional yield strength 430 MPa, ultimate tensile strength 574 MPa) with an acceptable level of electrical conductivity (46.1% IACS) and ductility (elongation to fracture ~ 5%) have been achieved. On the basis of the microstructural parameters determined by X-ray diffraction analysis and transmission electron microscopy, hardening mechanisms responsible for such high strength have been analyzed. It was shown that Cu plays the key role in strengthening. The addition of copper significantly contributes to grain refinement and, consequently, to grain-boundary hardening. Alloying with copper leads to significant additional hardening (~ 130 MPa) in the ultrafine-grained alloy, which is not typical for coarse-grained state. Segregation of Cu at grain boundaries and the formation of Cu nanoclusters are the most probable reasons for this hardening.

The Effect of Ultrafine-Grained Structure of Al-30Zn on the Shape Forming Ability at Sheet Metal Forming

2018 ◽  
Vol 385 ◽  
pp. 228-233
Author(s):  
Elena V. Bobruk ◽  
Denis G. Tyulenev ◽  
Oleg V. Golubev ◽  
Maxim Y. Murashkin
Keyword(s):  
Sheet Metal ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Aluminum Matrix ◽  
Test Method ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Ultrafine Grained

High pressure torsion (HPT) and equal channel angular pressing in parallel channels (ECAP-PC) at room temperature are used to form homogeneous ultrafine-grained (UFG) structure with a grain size of the aluminum matrix of 350 and 700 nm, respectively, in Al-30Zn (wt. %) specimens. The UFG samples with special geometry produced from the specimens processed by SPD techniques were subjected to sphere-shaped dimple extrusion testing (via the Erikson test method) and bended plate extrusion to determine the material formability during cold sheet metal forming. The same tests were performed on the material with coarse-grained (CG) structure for the sake of comparison. The obtained results are discussed.

Microstructure and Microhardness of a Nanostructured Nickel-Iron Based Alloy

2011 ◽  
Vol 683 ◽  
pp. 127-135 ◽  
Author(s):  
Shamil Kh. Mukhtarov ◽  
Xavier Sauvage
Keyword(s):  
High Pressure Torsion ◽  
Atom Probe ◽  
Coarse Grained ◽  
Temperature Phase ◽  
Nickel Iron ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Before And After ◽  
Iron Based ◽  
Electron Microscopes

This paper presents an overview and some original results about the mechanical properties and phase analysis of a nanostructured (NS) nickel-iron based alloy INCONEL 718. This structure was obtained by severe plastic deformation (SPD) via high pressure torsion (HPT) and multiple isothermal forging (MIF) of the alloy with an initial coarse-grained (CG) structure. Materials before and after SPD were analyzed by scanning, transmission electron microscopes and atom probe tomography (APT). Experimental data indicate that after HPT at room temperature - phase was partly dissolved and that precipitation of the -phase occurs during post deformation aging. A hardness up to 8 GPa was recorded for the NS alloy after SPD and annealing at 600°C.

Differences in Structural Evolution in Single- and Dual-Phase Materials during Severe Plastic Deformation

2006 ◽  
Vol 503-504 ◽  
pp. 407-412 ◽  
Author(s):  
Reinhard Pippan ◽  
A. Vorhauer ◽  
F. Wetscher ◽  
M. Faleschini ◽  
Martin Hafok ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Shear Strain ◽  
Single Phase ◽  
High Pressure Torsion ◽  
Structural Evolution ◽  
Dual Phase ◽  
Structural Elements ◽  
Transmission Electron ◽  
Electron Imaging

Severe plastic deformation (SPD) has been applied to two classes of metallic materials, single phase and dual phase materials. The applied shear strain has been varied between 1 and 1000 and the homologous temperature between 0.08 and 0.4. The deformation experiments are performed by high pressure torsion (HPT). The resulting microstructures were investigated by backscattered electron imaging, orientation image microscopy, and in selected cases by transmission electron microscopy. It will be shown that the behavior of single phase material is relatively uniform. With increasing strain, the size of the structural elements decreases and reaches a saturation between a shear strain of 10 to 100. The temperature and the alloying are the main parameters, which controls the saturation size of the structural elements (grains). The behavior in the dual phase materials is more complex, it varies from simple homogenisation, fragmentation of one phase, to desintegration and supersaturation of the phases.

High Pressure Torsion of Intermetallic Zr3Al

2008 ◽  
Vol 584-586 ◽  
pp. 553-558 ◽  
Author(s):  
David Geist ◽  
Christian Rentenberger ◽  
Hans Peter Karnthaler
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Structural Evolution ◽  
Nanocrystalline Structure ◽  
Temperature Dependent ◽  
Transmission Electron ◽  
Ordered Alloys ◽  
Grain Fragmentation ◽  
Shear Strains

The L12-structured intermetallic compound Zr3Al can be rendered amorphous easily by several techniques. In the present study the structural evolution during high pressure torsion (HPT) was investigated systematically by transmission electron microscopy (TEM) methods. Zr3Al samples were deformed at room temperature to different grades of deformation up to shear strains of 140 000%. TEM investigations revealed that the tendency to grain fragmentation, disordering and the formation of a nanocrystalline structure is weak compared to other L12 ordered alloys like Ni3Al. In addition, an amorphous phase has not been encountered. The present results differ strongly from previous ones obtained from ball-milled materials. Possible reasons for the different behavior are discussed on the basis of the temperature dependent dissociation scheme of the superlattice dislocations gliding in Zr3Al.

TEM Investigations of Titanium Processed by ECAP Followed by Cold Rolling

2006 ◽  
Vol 503-504 ◽  
pp. 805-810 ◽  
Author(s):  
Bernhard Mingler ◽  
V.V. Stolyarov ◽  
Michael Zehetbauer ◽  
Wolfgang Lacom ◽  
Hans Peter Karnthaler
Keyword(s):  
Cold Rolling ◽  
Room Temperature ◽  
High Strength ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Cp Ti ◽  
Annealing Experiments

Conventional coarse grained (CG) commercial pure (CP) Ti Grade 2 was studied after cold rolling (CR) at room temperature, and after equal channel angular pressing (ECAP) at 450° C followed by CR, by transmission electron microscopy (TEM) methods. CR of the CG material leads to a microstructure showing initially twins with (0112) type and later subgrains separated by lowangle grain boundaries. CR carried out after ECAP yields the fragmentation of fine grains (300 – 800 nm) mostly bounded by high-angle boundaries into elongated subgrains (~ 100 nm). It was shown with in-situ annealing experiments in the TEM that this microstructure is thermally stable up to a temperature of 450° C. Tensile tests showed that the combination of ECAP with CR has the potential to produce at the same time high strength (941 MPa) and high ductility (16.7%).

scholarly journals Use of Ring Sample for High-Pressure Torsion and Microstructural Evolution with Equivalent Strain

2008 ◽  
Vol 584-586 ◽  
pp. 191-196 ◽  
Author(s):  
Yuki Ito ◽  
Yosuke Harai ◽  
Tadayoshi Fujioka ◽  
Kaveh Edalati ◽  
Z. Horita
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
High Pressure Torsion ◽  
Equivalent Strain ◽  
Ring Sample ◽  
Transmission Electron ◽  
Low Dislocation Density ◽  
Data Points ◽  
Pure Cu ◽  
Hardness Values

This study introduces a process of high-pressure torsion (HPT) using ring samples and compares with the results of conventional disk HPT. Both types of HPT were conducted at room temperature on pure Al and pure Cu. The microhardness was measured along the diameters of the disks and rings. Microstructures were examined using transmission electron microscopy. When hardness values were plotted against equivalent strain, all data points fell on a single line for each material. There was a hardness maximum for pure Al but no such a maximum was present in pure Cu. In pure Al, many dislocations were visible within grains up to the equivalent strain corresponding to the hardness maximum but beyond this strain, grains with low dislocation density appear. All materials exhibited steady state where the hardness remains constant with respect to imposed equivalent strain. This study concludes that use of ring samples is effective as an alternative to the disk samples.

The Enhanced Kinetics of Precipitation Effects in Ultra Fine Grained Mg Alloys Prepared by High Pressure Torsion

2008 ◽  
Vol 273-276 ◽  
pp. 75-80 ◽  
Author(s):  
Jakub Čížek ◽  
Ivan Procházka ◽  
Bohumil Smola ◽  
Ivana Stulíková ◽  
Vladivoj Očenášek ◽  
...  
Keyword(s):  
High Pressure ◽  
Grain Boundaries ◽  
Volume Fraction ◽  
High Pressure Torsion ◽  
Mg Alloys ◽  
Coarse Grained ◽  
Fine Grained ◽  
Transmission Electron ◽  
Positron Lifetime Spectroscopy ◽  
Kinetics Of

Precipitation effects in ultra fine grained (UFG) lightweight Mg-based alloys were studied in the present work by means of positron lifetime spectroscopy, transmission electron microscopy, and microhardness. The UFG samples with grain size around 100 nm were fabricated by high pressure torsion (HPT). The UFG structure contains a significant volume fraction of grain boundaries and exhibits a high number of lattice defects (mainly dislocations) introduced by severe plastic deformation during the HPT processing. A high dislocation density and volume fraction of grain boundaries enhance the long range diffusion of solute elements. Moreover, dislocations and grain boundaries act as nucleation centers for precipitates. As a consequence, the precipitation effects are facilitated in the UFG alloys compared to the conventional coarse-grained samples. This phenomenon was examined in this work by comparison of the precipitation sequence in Mg alloys with UFG structure and solution treated coarse-grained alloys.

Phase Stability of the Al-Cu-Co Decagonal Phase Under Conventional Solidification

2009 ◽  
Vol 1242 ◽  
Author(s):  
J.O. Téllez-Vázquez ◽  
C. Patiño-Carachure ◽  
A. Bedolla-Jacuinde ◽  
E. García-De León ◽  
R. Pérez ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Structural Model ◽  
Alloy System ◽  
Phase Region ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Decagonal Phase ◽  
Transmission Electron ◽  
Thermal Stability Of

ABSTRACTAl65Cu15Co20 and Al67Cu13Co20 (% at.) alloys with composition near to the quasicrystalline decagonal phase was produced by melting in an induction furnace and solidified at room temperature. The structural characterization was carried out by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM). For the structural model of decagonal quasicrsytals, it is important to know which crystalline phases have a structural relationship on the formation and decomposition of this type of phases. In the present investigation, the decagonal phase usually coexist with small amounts of the Al(Cu,Co) cubic phase of B2 type. Then, the quasicrystalline (QC) phase is outside of a single-phase region under equilibrium conditions at room temperature. DSC and TGA techniques showed the thermal stability of the alloy system up to 1000 °C.

High Strength and Ductility of Nanostructured Al Alloy 2024 Subjected to High Pressure Torsion

2006 ◽  
Vol 114 ◽  
pp. 85-90 ◽  
Author(s):  
D. Vorona ◽  
Alfred V. Sharafutdinov ◽  
Nikolay A. Krasilnikov
Keyword(s):  
High Pressure ◽  
Room Temperature ◽  
Complex Geometry ◽  
High Pressure Torsion ◽  
Deformation Behaviour ◽  
Superplastic Forming ◽  
High Strength ◽  
Industrial Applications ◽  
Coarse Grained ◽  
Al Alloy

The structure and mechanical properties of Al-based alloy 2024 after high-pressure torsion (HPT) was investigated. Alloy 2024 with homogeneous structure and grain size about 70 nm was obtained using HPT at 6 GPa pressure and 5 turns of the anvils at room temperature. The nanostructured alloy possessed very high UTS (Ultimate tensile stress) above 1100 MPa at room temperature, and superplastic behaviour at temperatures over 300°С. The microhardness of the nanostructured alloy after superplastic deformation (1.5 GPa) was greater than that after the standard treatment of the coarse-grained alloy (1.2 GPa). The influence of HPT parameters and heat treatment on the structure and deformation behaviour of the alloy was studied. The opportunity of achieving a combination high strength and good ductility in metals and alloys opens perspectives for industrial applications, particularly, in micro-systems and for high-strength items with complex geometry which could be obtained by superplastic forming.

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