scholarly journals Structure Refinement and Fragmentation of Precipitates under Severe Plastic Deformation: A Review

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 601
Author(s):  
Boris B. Straumal ◽  
Roman Kulagin ◽  
Leonid Klinger ◽  
Eugen Rabkin ◽  
Petr B. Straumal ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Steady State ◽  
Severe Plastic Deformation ◽  
Defect Formation ◽  
Dynamic Equilibrium ◽  
Lattice Defect ◽  
Structure Refinement ◽  
Second Phase ◽  
Different Strains ◽  
State Saturation

During severe plastic deformation (SPD), the processes of lattice defect formation as well as their relaxation (annihilation) compete with each other. As a result, a dynamic equilibrium is established, and a steady state is reached after a certain strain value. Simultaneously, other kinetic processes act in opposite directions and also compete with each other during SPD, such as grain refinement/growth, mechanical strengthening/softening, formation/decomposition of solid solution, etc. These competing processes also lead to dynamic equilibrium and result in a steady state (saturation), albeit after different strains. Among these steady-state phenomena, particle fragmentation during the second phase of SPD has received little attention. Available data indicate that precipitate fragmentation slows down with increasing strain, though saturation is achieved at higher strains than in the case of hardness or grain size. Moreover, one can consider the SPD-driven nanocrystallization in the amorphous phase as a process that is opposite to the fragmentation of precipitates. The size of these crystalline nanoprecipitates also saturates after a certain strain. The fragmentation of precipitates during SPD is the topic of this review.

scholarly journals Deformation of Second Phase Particles in Al Alloy Using Severe Plastic Deformation Process

Materia Japan ◽  
2003 ◽  
Vol 42 (12) ◽  
pp. 863-863 ◽  
Author(s):  
Keiichiro Ohishi ◽  
Takeshi Fujita ◽  
Kunihiro Ohashi ◽  
Kenji Kaneko ◽  
Zenji Horita
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Process ◽  
Al Alloy ◽  
Second Phase ◽  
Severe Plastic Deformation Process ◽  
Plastic Deformation Process ◽  
Second Phase Particles

The Influence of Severe Plastic Deformation Process on Structure and Properties of AZ 31 Alloy after Selected Heat Treatment

2018 ◽  
Vol 275 ◽  
pp. 134-146
Author(s):  
Stanislav Rusz ◽  
Ondřej Hilšer ◽  
Stanislav Tylšar ◽  
Lubomír Čížek ◽  
Tomasz Tański ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Structure Refinement ◽  
Hardness Measurement ◽  
Az31 Alloy ◽  
Strength Properties ◽  
Aviation Industry ◽  
Initial State

The technology of structure refinement in materials with the aim of achieving substantial mechanical properties and maintaining the required plasticity level is becoming increasingly useful in industrial practice. Magnesium alloys are very progressive materials for utilization in practice thanks to their high strength-to-weight ratios (tensile strength/density). The presented paper analyses the effect of the input heat treatment of the AZ31 alloy on the change of structure and strength properties through the process of severe plastic deformation (SPD), which finds an increasing utilization, especially in the automotive and aviation industry. For the study of the influence of the SPD process (ECAP method) on the properties of the AZ31 alloy, two types of thermal treatment of the initial state of the structure were selected. The analysis of the structure of the AZ31 alloy was performed in the initial state without heat treatment and subsequently after heat treatment. In the next part, the influence of the number of passes on the strengthening curves was evaluated. Mechanical properties of the AZ31 alloy after ECAP were evaluated by hardness measurement and completed by structure analysis.

scholarly journals DIFFUSIVE AND DISPLACIVE PHASE TRANSFORMATIONS UNDER HIGH PRESSURE TORSION

2019 ◽  
Vol 25 (4) ◽  
pp. 230 ◽  
Author(s):  
Boris Straumal ◽  
Askar Kilmametov ◽  
Andrey Mazilkin ◽  
Olga Kogtenkova ◽  
Brigitte Baretzky ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Plastic Deformation ◽  
Grain Size ◽  
High Pressure ◽  
Phase Composition ◽  
Steady State ◽  
Phase Transformations ◽  
High Pressure Torsion ◽  
Dynamic Equilibrium ◽  
Initial State

<p class="AMSmaintext"><span lang="EN-GB">Severe plastic deformation (SPD) can induce various phase transformations. After a certain strain, the dynamic equilibrium establishes between defects production by an external force and their relaxation (annihilation). The grain size, hardness, phase composition etc. in this steady-state does not depend on the initial state of a material and is, therefore, equifinal. In this review we discuss the competition between precipitation and dissolution of precipitates, amorphization and (nano)crystallization, SPD-induced accelerated mass-transfer, allotropic and martensitic transitions and formation of grain boundary phases.</span></p>

Contributions of Various Strengthening Mechanisms to the Flow Onset Stress in the ECAP-Processed Cu-Cr-Zr Alloy

2017 ◽  
Vol 743 ◽  
pp. 197-202 ◽  
Author(s):  
Ilshat Faizov ◽  
Georgy I. Raab ◽  
Denis Aksenov
Keyword(s):  
Plastic Deformation ◽  
Phase Transitions ◽  
Severe Plastic Deformation ◽  
Structure Refinement ◽  
Strengthening Mechanisms ◽  
Dispersion Strengthening ◽  
Industrial Processing ◽  
The Common ◽  
Deformation Treatment ◽  
Zr Alloy

Various contributions to the overall strength of the Cu-1Cu-0.7Al-0.2Zr alloy after the combined severe plastic deformation treatment have been calculated and compared with those after the standard industrial processing. Contrary to the common viewpoint, the SPD increases the strength not only due to the structure refinement, but also because of greater contribution of the dispersion strengthening. It is argued that this effect is linked to the deformation-induced phase transitions upon the SPD.

Processing iron aluminides by heavy deformation for improved room temperature strength-ductility and for high temperature creep strength

2011 ◽  
Vol 1295 ◽  
Author(s):  
David G. Morris ◽  
Maria Antonia Muñoz-Morris
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Temperature ◽  
Severe Plastic Deformation ◽  
Creep Strength ◽  
Room Temperature ◽  
High Strain ◽  
Iron Aluminides ◽  
Al Alloy ◽  
Second Phase

ABSTRACTIron aluminides show many interesting properties, but still show relatively poor ductility at room temperature and only moderate creep resistance at temperatures above about 600ºC. Processes of severe plastic deformation have been investigated for a wide range of ductile alloys over the past decade, but have hardly been considered for intermetallics. This presentation discusses two studies aimed at refining microstructure by the use of severe plastic deformation of iron aluminides. The first considers processing Fe3Al by heavy cold rolling, followed by annealing for recovery or recrystallization, with an objective of refining grain size to improve strength at the same time as ductility. The high strength and poor ductility of the work hardened material leads to a danger of cracking during rolling, which is a problem for manufacturing large quantities of healthy material. Suitable rolling and recovery treatments can, nevertheless, lead to strong materials with some plastic ductility. A different technique of multidirectional, high-strain and high-temperature forging applied to a boride-containing Fe3Al alloy produces a material with large grain size and refined dispersion of boride particles. These particles lead to a considerable increase in creep strength under conditions of moderate stresses at temperatures around 700ºC. This high-strain forging technique can be seen as an intermediate processing method between conventional wrought metallurgy and mechanical-alloying powder metallurgy. This technique offers the possibility to improve high temperature behaviour of such intermetallics containing second-phase dispersions, and can be scaled to produce large quantities of high-quality material.

scholarly journals Effect of Severe Plastic Deformation on Structure Refinement and Mechanical Properties of the Al-Zn-Mg-Fe-Ni Alloy

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 296
Author(s):  
Irina Brodova ◽  
Dmitriy Rasposienko ◽  
Irina Shirinkina ◽  
Anastasia Petrova ◽  
Torgom Akopyan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
High Pressure ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Structure Refinement ◽  
Tensile Yield Strength ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Testing ◽  
Radial Shear Rolling

This paper identifies the mechanisms of phase and structural transformations during severe plastic deformation by shearing under pressure (high-pressure torsion) of an Al-Zn-Mg-Fe-Ni-based aluminum alloy depending on different initial states of the material (an ingot after homogenizing annealing and a rod produced by radial-shear rolling). Scanning and transmission electron microscopy are used to determine the morphological and size characteristics of the structural constituents of the alloy after high-pressure torsion. It has been found that, irrespective of the history under high-pressure torsion, fragmentation and dynamic recrystallization results in a nanostructural alloy with a high microhardness of 2000 to 2600 MPa. Combined deformation processing (high-pressure torsion + radial-shear rolling) is shown to yield a nanocomposite reinforced with dispersed intermetallic phases of different origins, namely Al9FeNi eutectic aluminides and MgZn2, Al2Mg3Zn3, and Al3Zr secondary phases. The results of uniaxial tensile testing demonstrate good mechanical properties of the composite (ultimate tensile strength of 640 MPa, tensile yield strength of 628 MPa, and elongation of 5%).

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