scholarly journals Review: Modes and Processes of Severe Plastic Deformation

2018 ◽  
Author(s):  
Vladimir Segal
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Simple Shear ◽  
Pure Shear ◽  
Deformation Mode ◽  
Strain Rates ◽  
Principal Characteristic ◽  
Structure Modification ◽  
Technological Parameters ◽  
Scalar Invariant

In this review, severe plastic deformation (SPD) is considered as a materials processing technology. The deformation mode is the principal characteristic differentiating SPD from common forming operations. For large plastic strains, deformation mode depends on the distribution of strain rates between continuum slip lines and can be varied from pure shear to simple shear. A scalar, invariant and dimensionless coefficient of deformation mode is introduced as a normalized speed of rigid rotation. On this basis, simple shear provides the optimum mode for structure modification and grain refinement whereas pure shear is "ideal" for forming operations. Special experiments and SPD practice confirm this conclusion. Various techniques of SPD are classified and described in accordance with simple shear realization or approximation. It is shown that correct analyses of the processing mechanics and technological parameters are essential for comparison of SPD techniques and the development of effective industrial technologies.

Texture Development in a Model Al-Li Alloy Subjected to Severe Plastic Deformation

2006 ◽  
Vol 114 ◽  
pp. 337-344 ◽  
Author(s):  
Bogusława Adamczyk-Cieślak ◽  
Jaroslaw Mizera ◽  
Krzysztof Jan Kurzydlowski
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Equal Channel Angular Extrusion ◽  
Orientation Distribution ◽  
X Ray Diffraction ◽  
Technological Parameters ◽  
Initial State ◽  
Texture Characteristic ◽  
X Ray ◽  
Ultrafine Grained

The texture of Al – 0.7 wt. % Li alloy processed by two different methods of severe plastic deformation (SPD) has been investigated by X-ray diffraction, and analyzed in terms of the orientation distribution function (ODF). It was found that severe plastic deformation by both Equal Channel Angular extrusion (ECAE) and Hydrostatic Extrusion (HE) resulted in an ultrafine grained structure in an Al – 0.7 wt. % Li alloy. The microstructure, grain shape and size, of materials produced by SPD strongly depend on the technological parameters and methods applied. The texture of the investigated alloy differed because of the different modes of deformation. In the initial state the alloy exhibited a very strong texture consisting of {111} fibre component. A similar fibrous texture characteristic was also found after HE whereas after the ECAE the initial texture was completely changed.

Superplasticity of Aerospace 7075 (Al-Zn-Mg-Cu) Aluminium Alloy Obtained by Severe Plastic Deformation

2018 ◽  
Vol 385 ◽  
pp. 39-44 ◽  
Author(s):  
Fernando Carreño ◽  
Oscar A. Ruano
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Aluminium Alloy ◽  
Room Temperature ◽  
Grain Boundary Sliding ◽  
Strain Rates ◽  
Aerospace Applications ◽  
Boundary Sliding ◽  
Processing Stress

The 7075 (Al-Zn-Mg-Cu) aluminium alloy is the reference alloy for aerospace applications due to its specific mechanical properties at room temperature, showing excellent tensile strength and sufficient ductility. Formability at high temperature can be improved by obtaining superplasticity as a result of fine, equiaxed and highly misoriented grains prone to deform by grain boundary sliding (GBS). Different severe plastic deformation (SPD) processing routes such as ECAP, ARB, HPT and FSP have been considered and their effect on mechanical properties, especially at intermediate to high temperatures, are studied. Refined grains as fine as 100 nm and average misorientations as high as 39o allow attainment of high strain rate superplasticity (HSRSP) at lower than usual temperatures (250-300oC). It is shown that increasing misorientations are obtained with increasing applied strain, and increasing grain refinement is obtained with increasing processing stress. Thus, increasing superplastic strains at higher strain rates, lower stresses and lower temperatures are obtained with increasing processing strain and, specially, processing stress.

Superplasticity in a 5024 Aluminium Alloy Processed by Severe Plastic Deformation

2012 ◽  
Vol 735 ◽  
pp. 353-358 ◽  
Author(s):  
Anna Mogucheva ◽  
Diana Tagirova ◽  
Rustam Kaibyshev
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Strain Rate ◽  
Aluminium Alloy ◽  
Initial Strain Rate ◽  
Strain Rates ◽  
Superplastic Behaviour ◽  
Angular Pressing ◽  
Elongation To Failure ◽  
Zr Alloy

The superplastic behaviour of an Al-4.6%Mg-0.35%Mn-0.2%Sc-0.09%Zr alloy was studied in the temperature range 250-500°C at strain rates ranging from 10-4 to 10-1 s-1. The AA5024 was subjected to equal channel angular pressing (ECAP) at 300°C up to ~12. The highest elongation-to-failure of ∼3300% was attained at a temperature of 450°C and an initial strain rate of 5.6×10-1 s-1. Regularities of superplastic behaviour of the 5024 aluminium alloy are discussed.

Achieving Superplasticity and Superplastic Forming through Severe Plastic Deformation

2000 ◽  
Vol 634 ◽  
Author(s):  
Minoru Furukawa ◽  
Zenji Horita ◽  
Terence G. Langdon
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Elevated Temperatures ◽  
Superplastic Forming ◽  
Ultrafine Grain ◽  
Strain Rates ◽  
Grain Sizes ◽  
Angular Pressing ◽  
Large Bulk ◽  
Processing Procedure

ABSTRACTThe application of severe plastic deformation to metals provides a convenient procedure for achieving nanometer and submicrometer microstructures. Several different processing methods are available but Equal-Channel Angular Pressing (ECAP) is especially attractive because it provides an opportunity for preparing relatively large bulk samples. This paper describes the use of ECAP in preparing materials with ultrafine grain sizes and the subsequent properties of these materials at elevated temperatures. It is demonstrated that, provided precipitates are present to retain these small grain sizes at the high temperatures where diffusion is reasonably rapid, it is possible to achieve remarkably high superplastic elongations in the as-pressed materials and there is a potential for making use of this processing procedure to develop a superplastic forming capability at very rapid strain rates.

Deformation-Induced Microstructure Effects on Ultrasonic Waves: Simple Shear Versus Pure Shear

2006 ◽  
Author(s):  
S. H. Tang ◽  
S. Wu
Keyword(s):  
Plastic Deformation ◽  
Point Defects ◽  
Simple Shear ◽  
Pure Shear ◽  
Fractal Dimensions ◽  
Ultrasonic Waves ◽  
Striking Difference ◽  
Wave Velocities ◽  
Microstructure Effects ◽  
Deformation Modes

Although similar in total strain in simple shear and pure shear, they are very diverse in deformation modes, and the effect of these deformation modes on ultrasonic waves is very different. This paper aims to investigate deformation-induced microstructures and their effects on ultrasonic waves under simple and pure shear states. Texture evolutions, plastic spins, point defects induced by cross slips and fractal dimensions are analyzed via finite element polycrystal model. The investigation indicates that the texture evolutions are the same and transverse wave velocities depend on textures mainly; however, the point defects induced by cross slips show a striking difference between simple shear and pure shear, this implies that longitudinal wave velocities are sensitively influenced by point defects during plastic deformation.

Hot Workability of Ultrafine-Grained Aluminum Alloy Produced by Severe Plastic Deformation of Al6063 Powder and Consolidation

2010 ◽  
Vol 667-669 ◽  
pp. 979-984 ◽  
Author(s):  
Hamed Asgharzadeh ◽  
Abdolreza Simchi ◽  
Hyoung Seop Kim
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Dynamic Recrystallization ◽  
Strain Rate ◽  
Hot Deformation ◽  
Grain Structure ◽  
Al Alloy ◽  
Strain Rates ◽  
Hot Workability ◽  
Ultrafine Grained

Al6063 powder was subjected to severe plastic deformation via high-energy mechanical milling to prepare ultrafine-grained (UFG) aluminium alloy. Uniaxial compression test at various temperatures between 300 and 450 °C and strain rates between 0.01 and 1 s-1 was carried out to evaluate hot workability of the material. Microstructural studies were performed by EBSD and TEM. The average activation energy and strain rate sensitivity of the hot deformation process were determined to be 280 kJ mol-1 and 0.05, respectively. The deformation temperature and applied strain rate significantly affected the grain structure of UFG Al alloy. A finer grain structure was obtained at lower temperatures and higher strain rates. The formation of highly misoriented and equiaxed grains also revealed that dynamic recrystallization occurred upon hot deformation. Furthermore, elongated grains with high dislocation density were observed that disclosed partial dynamic recrystallization of the aluminum matrix.

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