Deformation Mechanisms and Ductility of Nanostructured Al Alloys

2004 ◽  
Vol 821 ◽  
Author(s):  
Bing Q. Han ◽  
Farghalli A. Mohamed ◽  
Enrique J. Lavernia
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Aluminum Alloys ◽  
Severe Plastic Deformation ◽  
Work Hardening ◽  
Tensile Ductility ◽  
High Strength ◽  
Al Alloys ◽  
Deformation Mechanisms ◽  
Coarse Grains

AbstractLow tensile ductility is one of the critical challenges facing the science and technology of nanostructured materials. As an example, despite the fact that high strength is frequently observed in bulk nanostructured Al alloys, ductility and work hardening are often observed to decrease with decreasing grain size. In the present study, the tensile ductility of bulk nanostructured aluminum alloys processed via severe plastic deformation and consolidation of mechanically milled powders is analyzed. Adding coarse grains to the nanostructured matrix is proposed as an approach to improve ductility.

Severe Plastic Deformation under High Pressure for Production of Superplastic Materials

2016 ◽  
Vol 838-839 ◽  
pp. 287-293 ◽  
Author(s):  
Zenji Horita
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
High Pressure Torsion ◽  
High Strength ◽  
Al Alloys ◽  
Strain Rates ◽  
Ti Alloys

Grain refinement is an important prerequisite for advent of superplasticity. In particular, as the grain size is smaller, the superplasticity appears at higher strain rates and lower temperatures. Severe plastic deformation (SPD) is a useful process for achieving significant grain refinement. This presentation shows that applicability of the SPD process is enhanced when it is operated under high pressure through high-pressure torsion (HPT) and high-pressure sliding (HPS). It is demonstrated that commercially available conventional alloys but less ductile alloys such as Mg alloys, age-hardenable high-strength Al alloys (A2024, A7075) and Ti alloys become superplastic after processing by HPT or HPS.

Investigations on Microstructure Evolution and Deformation Behavior of Aged and Ultrafine Grained Al-Zn-Mg Alloy Subjected to Severe Plastic Deformation

2010 ◽  
Vol 667-669 ◽  
pp. 253-258
Author(s):  
Wei Ping Hu ◽  
Si Yuan Zhang ◽  
Xiao Yu He ◽  
Zhen Yang Liu ◽  
Rolf Berghammer ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Microstructure Evolution ◽  
Deformation Behavior ◽  
Deformation Mechanisms ◽  
Mg Alloy ◽  
Ultrafine Grained

An aged Al-5Zn-1.6Mg alloy with fine η' precipitates was grain refined to ~100 nm grain size by severe plastic deformation (SPD). Microstructure evolution during SPD and mechanical behaviour after SPD of the alloy were characterized by electron microscopy and tensile, compression as well as nanoindentation tests. The influence of η' precipitates on microstructure and mechanical properties of ultrafine grained Al-Zn-Mg alloy is discussed with respect to their effect on dislocation configurations and deformation mechanisms during processing of the alloy.

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

scholarly journals Investigation of tribotechnical and corrosion behaviour of material for light-alloy drill pipes

2018 ◽  
Vol 18 (1) ◽  
pp. 21-27
Author(s):  
Alina I. Shakirova ◽  
Rustem A. Ismakov ◽  
Akhtyam Kh. Agliullin ◽  
Nikolai K. Tsenev
Keyword(s):  
Plastic Deformation ◽  
Aluminum Alloys ◽  
Severe Plastic Deformation ◽  
Sliding Friction ◽  
Corrosion Behaviour ◽  
High Strength ◽  
The Arctic ◽  
Light Alloy ◽  
Pipe Surface ◽  
Drill Pipes

Special aluminum alloys appear to be promising materials for manufacture of high-strength light-alloy drill pipes (HSLADP) that can be used in areas with a severe climate and challenging geology. The effect of using light-alloy drill pipes (LADP) depends directly on the properties of the aluminum alloys from which such pipes are made. As the wells become deeper and horizontal wellbores get longer, use of LADPs becomes more relevant. Since light-alloy pipes are 2.8 times softer than steel pipes, LADPs offer the same performance as steel drill pipes of the lowest strength grade even in the case of rotary drilling. The materials from which such pipes are made have a number of unique advantages: extra light weight in the drill mud, allowing the coefficient of sliding friction between the pipe surface and the borehole wall to be reduced; high corrosion resistance in aggressive media with A high concentration of hydrogen sulfide and carbon dioxide; and high magnetic inductive capacity that allows LADPs to be used as a housing for MWD (measurement while drilling) and LWD (logging while drilling) telemetry systems during well-drilling operations. This study suggests methods for industrial production of submicrocrystalline (SMC) structure in aluminum alloys with the help of severe plastic deformation. Through the example of model aluminum-lithium alloys 1420 (Al-Mg-Li-Zr) and 1460 (Al-Сu-Li-Zr), the researchers demonstrate that SMC structure helps significantly increase resistance to wear and reduce the rate of corrosion depending on the pH value. The research team also states that severe plastic deformation methods may be used to develop highly promising technologies for manufacture of high-strength LADPs with advanced strain-stress properties for use during operations in the Arctic.

Features of Work Hardening of Polycrystals with Nanograins

2008 ◽  
Vol 584-586 ◽  
pp. 35-40 ◽  
Author(s):  
Eduard Kozlov ◽  
Nina Koneva ◽  
L.I. Trishkina ◽  
A.N. Zhdanov ◽  
M.V. Fedorischeva
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Work Hardening ◽  
Mechanical Characteristics ◽  
Grain Boundary Sliding ◽  
Deformation Mechanisms ◽  
Dislocation Slip ◽  
Grain Sizes ◽  
Boundary Sliding ◽  
Size Interval

The present work is devoted to the investigation of the influence of the grain size on the main mechanical characteristics of nanopolycrystals of different metals. The Hall-Petch parameter behaviour for Al, Cu, Ni, Ti and Fe was examined in the wide grain size interval. The stages of plastic deformation and the parameters of work hardening for nanocrystalline copper were analysed in detail. The deformation mechanisms and critical grain sizes accounting for the transition from the dislocation slip to the grain boundary sliding were described.

scholarly journals Strengthening of Copper by Using RCS Process and Optimization Through Taguchi Method

2019 ◽  
pp. 187-193
Author(s):  
Jwala Sudheer Reddy ◽  
U. Mahaboob Basha ◽  
L. Balasubramanyam ◽  
S. Jithendra Naik
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Optimization Technique ◽  
High Strength ◽  
Ultrafine Grain ◽  
Taguchi Optimization ◽  
Fine Grained ◽  
Safety And Reliability ◽  
Micro Parts

Severe plastic deformation (SPD) Processes is to be determined as metal forming processes in which a very large plastic strain is imposed on a bulk process in which to make an ultra-fine-grained metal. Generating an ultrafine grained metal is to allow lightweight parts by using high strength metal for the safety and reliability of micro-parts and for eco-friendly, is the main intention of SPD Processes. In Severe plastic deformation processes (SPD), repetitive corrugation and straightening (RCS) are one of the new technical processes, in which the grain size is reduced to ultrafine grain size then the strength of copper is going to be increased by using this process in this project. The Taguchi optimization technique is utilized with conventional orthogonal array L9, in which to determine the process parameters are statistically significant on hardness. Finally, the verification test was carried out to investigate optimization enhancements.

Fatigue of Ultra-Fine Grained α-Brass

2014 ◽  
Vol 891-892 ◽  
pp. 1125-1130
Author(s):  
Yoshikazu Nakai ◽  
Takuto Imanaka ◽  
Daiki Shiozawa
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Severe Plastic Deformation ◽  
Fatigue Limit ◽  
High Strength ◽  
Angular Pressing ◽  
Fine Grain ◽  
Proof Strength

Combined methods to obtain ultra-fine grain (UFG) α-brass samples are proposed. Severe plastic deformation followed by recrystallization was conducted, where multiple rolling and equal channel angular pressing (ECAP) were employed. Recrystallization was accomplished by heat-treatment after the severe plastic deformation, and the grain size after the severe plastic deformation was decreased. By multiple rolling, plates with thickness of 0.1 mm and grain size of 1.0 μm were obtained. By ECAP process, square bar with cross-section of 6 mm × 6 mm and minimum grain size of 4.1 μm was obtained. The 0.2 % proof strength, ultimate tensile strength, and fatigue limit were increased with the value of inverse square root of grain size (Hall-Petch relationship). Then, the 0.2 % proof strength of UFG brass was tenfold, the ultimate tensile strength and the fatigue limit were two fold increases from the conventional α-brass. Because of the high strength, the scatter of fatigue strength of UFG brass was large, which reflects the sensitivity to defects in material.

Improvement of Mechanical Properties and Microstructure of Al-Fe-Si Alloy by ECAP Semisolided Method

2010 ◽  
Author(s):  
D. Azimi-Yancheshmeh ◽  
M. Aghaie-Khafri
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Solid Phase ◽  
High Strength ◽  
Ultrafine Grains ◽  
Ecap Process ◽  
Hardness Tests ◽  
Heat Treated

ECAP is one of the Severe Plastic Deformation methods for reducing the grain size. With this process we can achieve ultrafine grains and consequently high strength. In this study, ECAP process was done on Al-Fe-Si alloy. This alloy was considered because of Fe effect on refining grain size. All samples were ECAPed into 1 pass in ECAP mold with 2 equal channels (1 cm × 1 cm) with 90 degree between them. By this method, around 1.05 as strain was applied on each samples. ECAPed specimens were heat treated (Semisolided) in different times and temperatures for achieving good toughness. Compression and hardness tests were done for finding the mechanical properties. As a result of these test, specimens that tolerate both ECAP and Semisolid have better toughness and strength than received and only ECAPed samples. Based on the microstructural evaluations spheroid solid phase was observed in the Semisolid specimen.

Determination of Mechanical Properties on Aluminium with 5% Copper Powder Metallurgy Route Compacts through Equal Channel Angular Pressing

2015 ◽  
Vol 813-814 ◽  
pp. 161-165
Author(s):  
M. Sadhasivam ◽  
T. Pravin ◽  
S. Raghuraman
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Grain Size ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Pressing ◽  
High Strength ◽  
Angular Pressing ◽  
Fine Grain ◽  
Plastic Deformation Process

The need for super-plasticity and high strength leads to the development of Severe Plastic Deformation technique. The strength of the material is directly dependent upon the grain size of the material. So, there is a need for producing Ultra-Fine Grain microstructure (UFG). UFG material is the material with very small grain size in the range of sub-micrometre. Application of severe plastic deformation, imparts extremely high strain. Equal channel angular pressing (ECAP) is a severe plastic deformation process in which the metal specimen is pressed through an angular channel of equal cross section. The material is subjected to shear deformation and strain is imparted in the specimen. Geometric parameters such as channel angle and corner angle play a major role in grain refinement. Aluminium (Al) specimens are subjected to undergo severe plastic deformation. Since, the strength of Al is not high, other materials are added in order to enhance its mechanical properties by matrix work hardening. Copper (Cu) along with Al shows increase in its strength and also in hardness. An attempt is made with Aluminium and copper, blended in the ratio 95:5 by weight with the main objective to study the Tensile strength, Hardness and Percentage Elongation properties of the specimen.

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