Production of Ultra-Fine-Grained Aluminum Plates by Constrained Groove Pressing Technique

2013 ◽  
Author(s):  
Hadi Miyanaji ◽  
Ali Keshavarz Panahi ◽  
Ramin Hajavifard
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Plastic Strain ◽  
Yield Strength ◽  
The Other ◽  
Fine Grained ◽  
New Methods ◽  
Pressing Operation ◽  
Resistance To Wear ◽  
Aluminum Plates

One of the new methods of producing materials that have ultra-fine grains or grains of nanometer size is the method of severe plastic deformation (SPD). In this technique, by applying severe strains to the samples, the size of the grains is reduced to the nano scale, and as a result, the mechanical properties of the metal (including the yield strength and resistance to wear and abrasion) improve considerably. In this research, the effect of the constrained groove pressing process (as one of the SPD methods) on aluminum plates was studied. In this method, two dies (one with asymmetrical grooves, and the other, flat) were used for pressing the aluminum samples. With respect to the die’s geometry, at each pressing run, a shear strain equal to 0.58 is applied to some parts of the sample. By repeating the pressing operation, a large and significant amount of plastic strain is applied throughout the sample. In the present investigation, tensile and microhardness tests were employed to determine the effect of this process on the mechanical properties of the samples,. The results showed that, by increasing the number of pressing steps, hardness and strength of the samples increase, and the elongation ability diminishes. Of course, at higher numbers of pressing steps, a little decrease in strength was observed in the samples. Complete explanations regarding this decrease have been given in the text of the article.

The Cyclic Extrusion Behavior of Severe Plastic Deformation (CEC) of Aluminum Alloy 6061

2020 ◽  
Vol 835 ◽  
pp. 186-192
Author(s):  
Gehan A. Abd El Raouf ◽  
N. El Mahallawy ◽  
M.K. Shoukry
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Plastic Strain ◽  
Severe Plastic Deformation ◽  
Bulk Material ◽  
Aluminum Alloy 6061 ◽  
Fine Grained ◽  
Before And After ◽  
Alloy 6061

Cyclic extrusion compression (CEC) is one of the well-known techniques in metal forming processes under the severe plastic deformation process (SPD) in which an ultra-large plastic strain is imposed on a bulk material in order to make ultra-fine grained (UFG) metals, alloys and composites. In this work, the mechanical properties of the aluminum alloy (6061) before and after CEC process were examined. A special CEC die was design and fabricated for the present work which achieved an effective plastic strain of about 0.62 after each separate cycle of CEC. The microstructure was effectively refined with increasing the number of CEC cycles as the grain size was reduced from ≈250μm to ≈30 μm after 6 cycles of CEC. The mechanical properties were tremendously increased in comparison with those of as cast and annealed condition. The micro-hardness increased from 25 Hv to 56 Hv, while the yield and the ultimate tensile strengths increased from 60 MPa to 198 MPa and 85 MPa to 204 MPa respectively, the ductility increased from 2.97% to 4.6% with the number of CEC cycles increasing up to six cycles.

Correlation among Microstructure, Texture, and Properties along the Thickness Direction in As-Hot-Rolled and As-Solution-Quenched Al7055 Thick Plates

2021 ◽  
Vol 1026 ◽  
pp. 65-73
Author(s):  
Kai Zhu ◽  
Hong Wei Yan
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Tensile Tests ◽  
Rolled Plate ◽  
Uniaxial Tensile ◽  
Thickness Direction ◽  
Electron Backscattered Diffraction ◽  
Thick Plates ◽  
Aluminum Plates ◽  
Hot Rolled

Both microstructure inhomogeneity and mechanical property diversity along the thickness direction in rolled thick aluminum plates have been considered to have a remarkable impact on the performance and properties of the products made from the plates. In this study, scanning electron microscopy (SEM) and electron backscattered diffraction (EBSD) characterizations of microstructure and texture types along the thickness directions of Al7055 thick plate specimens prepared using two conditions, hot-rolling and solution-quenching, were performed. To examine the mechanical properties, uniaxial tensile tests were also carried out on specimens machined from both types of thick plates, using a layered strategy along the thickness direction. The results indicate that both the microstructure and mechanical properties are inhomogeneous under the two conditions. Furthermore, it is evident that there is a hereditary relationship between the mechanical properties of the two plates—areas with higher yield strength in the as-hot-rolled plate correspond to areas with the higher yield strength in the as-solution-quenched plate

Paradox of Strength and Ductility in Metals Processed Bysevere Plastic Deformation

2002 ◽  
Vol 17 (1) ◽  
pp. 5-8 ◽  
Author(s):  
R. Z. Valiev ◽  
I. V. Alexandrov ◽  
Y. T. Zhu ◽  
T. C. Lowe
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
High Strength ◽  
High Ductility ◽  
Elongation To Failure ◽  
Failure Ductility ◽  
Strength And Ductility

It is well known that plastic deformation induced by conventional forming methodssuch as rolling, drawing or extrusion can significantly increase the strength of metalsHowever, this increase is usually accompanied by a loss of ductility. For example, Fig.1 shows that with increasing plastic deformation, the yield strength of Cu and Almonotonically increases while their elongation to failure (ductility) decreases. Thesame trend is also true for other metals and alloys. Here we report an extraordinarycombination of high strength and high ductility produced in metals subject to severeplastic deformation (SPD). We believe that this unusual mechanical behavior is causedby the unique nanostructures generated by SPD processing. The combination ofultrafine grain size and high-density dislocations appears to enable deformation by newmechanisms. This work demonstrates the possibility of tailoring the microstructures ofmetals and alloys by SPD to obtain both high strength and high ductility. Materialswith such desirable mechanical properties are very attractive for advanced structuralapplications.

scholarly journals Microstructure and Mechanical Behavior of Al-Mg Composites Synthesized by Reactive Sintering

Metals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 762 ◽  
Author(s):  
Rub Nawaz Shahid ◽  
Sergio Scudino
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Yield Strength ◽  
Mechanical Behavior ◽  
Intermetallic Compounds ◽  
Metal Matrix ◽  
Stress Model ◽  
Matrix Composites ◽  
Reactive Sintering ◽  
Powder Mixtures

Lightweight metal matrix composites are synthesized from elemental powder mixtures of aluminum and magnesium using pressure-assisted reactive sintering. The effect of the reaction between aluminum and magnesium on the microstructure and mechanical properties of the composites due to the formation of β-Al3Mg2 and γ-Al12Mg17 intermetallics is investigated. The formation of the intermetallic compounds progressively consumes aluminum and magnesium and induces strengthening of the composites: the yield and compressive strengths increase with the increase of the content of intermetallic reinforcement at the expense of the plastic deformation. The yield strength of the composites follows the iso-stress model when the data are plotted as a function of the intermetallic content.

Full Scale Reeling Simulation Tests of Girth Welded X60 HFW Linepipe

2016 ◽  
Author(s):  
Teruki Sadasue ◽  
Satoshi Igi ◽  
Kenji Oi ◽  
Satoru Yabumoto
Keyword(s):  
Brittle Fracture ◽  
Plastic Strain ◽  
Yield Strength ◽  
Tensile Properties ◽  
Local Buckling ◽  
Full Scale ◽  
The Other ◽  
Simulation Test ◽  
Other Hand ◽  
Girth Welds

The reel-lay method is a fast and cost efficient installation process for offshore rigid steel pipelines. Pipelines installed by the reel-lay method are plastically deformed due to reeling, unreeling, aligning and straightening during pipeline installation. Therefore, local buckling is one of the major concerns from a view point of integrity in linepipes, especially around girth welds where strength mismatching arises due to adjacent pipes with different yield strength. One the other hand, the change in mechanical properties of linepipes during reel-lay, including coating process (e.g. 250°C) and long time exposure (e.g. 250°C aging) after installation is also important in order to guarantee safety of linepipes. Furthermore fracture toughness at girth weld Coarse-grain HAZ (CGHAZ) after reeling and aging should be clear to prevent brittle fracture of offshore linepipes in service. In this study, full scale reeling simulation tests of girth welded X60 HFW (High Frequency electric resistance Welded) linepipes with OD; 323.9mm and WT;15.9mm after full body heat treatment (coating simulation) were conducted at 5cycles and 2cycles reeling and straightening situations when yield strength mismatches are present between adjacent pipes around girth welds. Localized strain concentration was observed near girth welds by strength mismatching of adjacent pipes. DNV ovality increased with increasing reeling and straightening cycles, however the ovality did not exceed 10%, which was a criterion value for local buckling, after 5cycles reeling simulation test. The change ratio of wall thickness after full scale reeling simulation tests were about ±2% (within DNV-OS-F101 tolerance) regardless of circumferential and longitudinal direction of pipes. Longitudinal tensile properties could be characterized by axial last introduced plastic strain. That is, in the positive number of last introduced plastic strain, YS and Y/T increased, while uEl decreased by work hardening effect. On the other hand YS and Y/T decreased, while uEl increased at the negative number of last introduced plastic strain by Bauschinger effect. Circumferential tensile properties could be also characterized by axial last introduced plastic strain. Yield strength and Y/T slightly increased while uniform elongation slightly decreased by aging at longitudinal and circumferential direction. Tensile properties did not change irrespective of the number of cycles of reeling simulation tests. After 5cycles reeling simulation test and aging, girth welded CGHAZ CTOD values were over 0.4mm at −20°C and Charpy absorbed energy were over 200J at −30°V, therefore, it was considered that the brittle fracture of the girth welded linepipe unlikely occur at reeling and aging situation in this study.

Effects of Cu on mechanical properties and corrosion resistance on (Ti36.1Zr33.2Ni5.8Be24.9)100-xCux alloys

2020 ◽  
Vol 10 (6) ◽  
pp. 812-818
Author(s):  
Xiangjie Yang ◽  
Xinhua Huang ◽  
Linhao Zhu ◽  
Hongmin Guo ◽  
Hualan Jin
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Thermal Properties ◽  
Plastic Strain ◽  
Yield Strength ◽  
Metallic Glass ◽  
High Strength ◽  
Mechanical Behaviors ◽  
Cu Content ◽  
Mechanical Properties And Corrosion

Due to high strength, perfect plasticity and higher hardness, bulk metallic glass (BMG) has been widely concerned. The work used the vaccum casting of copper-formed mold to establish (Ti36.1Zr33.2Ni5.8Be24.9)100-xCux, where x = 3, 5, 7, 9 and 11. Thermal properties, mechanical behaviors of compression, and corrosion resistance in the proposed compounds were investigated. The results show that the increase in Cu content enhances the heat resistance and the forming of glass of BMGs, small amount of fine dendritic crystals presents in BMG when x = 3, and the best corrosion resistance and mechanical properties can be obtained when x = 7, the yield strength, fracture strength and plastic strain can reach 1496.15 MPa, 2003.44 MPa and 19.19%, respectively.

Recrystallization and Grain Growth in Ultra Fine Grained Materials Produced by High Pressure Torsion

2012 ◽  
Vol 715-716 ◽  
pp. 373-373
Author(s):  
Anahita Khorashadizadeh ◽  
Myrjam Winning ◽  
Stefan Zaefferer ◽  
Dierk Raabe
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Grain Growth ◽  
High Pressure Torsion ◽  
Fine Grained ◽  
Fine Grained Material

Investigations of the microstructure of materials processed via severe plastic deformation methods such as high pressure torsion (HPT) and their recrystallization behaviour is of great interest as they are capable of producing ultra fine grained material (UFD) with good mechanical properties.

Compressive and Shearing Mechanical Anisotropy of Aluminum after ECAP

2014 ◽  
Vol 1016 ◽  
pp. 100-104
Author(s):  
Cleber Granato de Faria ◽  
Tércio Assunção Pedrosa ◽  
Roberto Braga Figueiredo ◽  
Maria Teresa Paulino Aguilar ◽  
Paulo Roberto Cetlin
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Cross Section ◽  
High Strain ◽  
High Strength ◽  
The Other ◽  
Mechanical Anisotropy ◽  
Single Plane ◽  
Angular Pressing ◽  
Very High

Severe plastic deformation (SPD), where metals are deformed up to very high strain values, leads to a very small grain size and a high strength of the material. ECAP (Equal Channel Angular Pressing) is one of the SPD methods, and involves the extrusion of a metal billet through two intersecting channels with identical cross-section and forming an angle between them. The material undergoes shearing as it crosses from one channel to the other, but its external dimensions are not altered. Shearing occurs along a single plane, which may lead to anisotropy in the mechanical properties of the material after ECAP. Compression, tension and shearing tests along various directions in the as-processed specimens indicated the presence of mechanical anisotropy in ECAP processed aluminum.

scholarly journals Effect of initial temper on mechanical properties of creep-aged Al-Cu-Li alloy AA2050

2018 ◽  
Vol 190 ◽  
pp. 12006
Author(s):  
Yong Li ◽  
Yo-Lun Yang ◽  
Qi Rong ◽  
Zhusheng Shi ◽  
Jianguo Lin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Yield Strength ◽  
Uniform Elongation ◽  
Tensile Tests ◽  
Third Generation ◽  
Rate Analysis ◽  
Precipitation Behaviour ◽  
Work Hardening Rate ◽  
Creep Age Forming

The evolution of mechanical properties of a third generation Al-Cu-Li alloy, AA2050, with different initial tempers (T34 and as-quenched (WQ)) during creep-ageing has been investigated and analysed in this study. A set of creep-ageing tests under 150 MPa at 155 °C for up to 24 h was carried out for both initial temper conditions and tensile tests were performed subsequently to acquire the main mechanical properties of the creep-aged alloys, including the yield strength, ultimate tensile strength (UTS) and uniform elongation. Precipitation behaviour of the T34 and WQ AA2050 alloys has been summarised and successfully explains the detailed evolutions of the obtained mechanical properties of the alloy with these two initial tempers during creep-ageing. The results indicate that the T34 alloy can be a better choice for creep age forming (CAF) process compared with WQ alloy, as it provides better yield strength and uniform elongation properties concurrently after creep-ageing. In addition, a work hardening rate analysis has been carried out for all the creep-aged alloys, helping to reveal the detailed dislocation/precipitates interaction mechanisms during plastic deformation in the creep-aged T34 and WQ AA2050 alloys.

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