Thermal deformation behavior and processing maps of 7075 aluminum alloy sheet based on isothermal uniaxial tensile tests
TL;DR: In this paper, thermal-mechanical properties of aluminum alloys under hot forming conditions were comprehensively investigated using a series of isothermal uniaxial tensile tests at different temperatures and strain rates on a Gleeble 3500 thermal mechanical simulator.
About: This article is published in Journal of Alloys and Compounds.The article was published on 2018-10-30. It has received 84 citations till now. The article focuses on the topics: Work hardening & Strain rate.
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15 Feb 2021-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, 2195 aluminum alloy was compressed at 300-520°C using a Gleeble 3500-GTC thermo-mechanical testing system and the discontinuous dynamic recrystallization (DDRX) and continuous dynamic re-structure (CDRX), and the results demonstrated that during medium temperatures (300-360°C) deformation the main softening mechanism was DDRX, and at high temperatures (420-520 °C), it was CDRX.
Abstract: The 2195 aluminum alloy has been widely utilized in the aerospace field, of which dynamic recrystallization microstructures have a substantial effect on the mechanical properties of aerospace parts. In this study, 2195 aluminum alloy was compressed at 300–520 °C using a Gleeble 3500-GTC thermo-mechanical testing system. The discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) behavior of 2195 aluminum alloy at medium/high temperature was studied. The results demonstrated that during medium temperatures (300–360 °C) deformation the main softening mechanism was DDRX, and at high temperatures (420–520 °C), it was CDRX. CDRX of 2195 aluminum alloy involved three types of subgrain-forming mechanisms: dislocation tangling to form subgrains, microscopic shear bands to form subgrains, and the coalescence of two small subgrains to form larger subgrains. In addition, several recrystallized grains underwent geometric dynamic recrystallization (GDRX) at high temperature and extensive deformation (480 °C-80% or 520 °C-60%).
68 citations
24 Jun 2019-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this paper, the mechanical behavior and deformation mechanism of 7075 aluminum alloy sheets under dynamic strain aging induced by solution treatment were investigated, and the results showed that the dissolution of secondary phase occurs during heat treatment, accompanied by coarsening behavior at lower temperatures, which leads to the transition characteristics of mechanical properties of the aluminum alloy in solid solution state.
Abstract: In this study the mechanical behavior and deformation mechanism of 7075 aluminum alloy sheets under dynamic strain aging induced by solution treatment were investigated. The uniaxial tensile tests were carried out at various strain rates (8.33 × 10−5 s−1, 1.67 × 10−3 s−1, 3.33 × 10−2 s−1 and 1.33 × 10−1 s−1) for samples treated by different solution processes (solution for 30 min at temperatures of 573 K, 623 K, 673 K and 748 K, and then quenching). The Portevin-Le Chatelier (PLC) effect (i.e., serration types of stress-strain curves, strain rate sensitivity (SRS) and critical strain) were analyzed, causing changes in tensile strength, work hardening rate and elongation. The morphology, sizes and quantities of precipitates under different solution-quenching conditions were observed by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that the dissolution of secondary phase occurs during heat treatment, accompanied by coarsening behavior at lower temperatures, which leads to the transition characteristics of mechanical properties of the aluminum alloy in solid solution state. There exists a critical point of solution temperature (623K), namely, when the solution temperature is lower than this critical point, the microstructure after quenching is mainly composed of the matrix and secondary phase; otherwise it is mainly composed of solid solution. Therefore, the samples heated at different solution temperatures have different types of PLC effects. It is worth noting that the strong effect of dynamic strain aging induced at high solution temperature and low strain rate could simultaneously enhance the strength and toughness.
47 citations
TL;DR: In this paper, the thermal deformation behavior of 3Cr23Ni8Mn3N heat resistant steel was studied by high-temperature thermal compression test in the deformation temperature range of 1000-1180°C, the strain rate range of 0.03-0.10−1 and deformation degree of 60%.
42 citations
TL;DR: In this paper, a modified continuum damage model was proposed to describe the damage evolution and predict the fracture behavior of AA7075 at elevated temperatures (300-400 °C), where the uniaxial equations were extended into a set of multi-axial CDCEs by introducing a multiaxial damage correction formula to predict the TFLD.
40 citations
TL;DR: In this article, a mesoscopic damage model was implemented to take account of the damage evolution phenomenon of AA7075 at elevated temperatures, and the temperature-dependent damage void volume fractions (VVF) were identified accurately based on a novel inverse identification procedure, named the CCD parameters design-FEM inverse simulation-genetic algorithm (CCD-FEIS-GA).
37 citations
References
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07 Nov 1996
TL;DR: In this paper, the authors discuss the extent to which we are able to formulate quantitative, physically-based models which can be applied to metal-forming processes, and the subjects treated in this book are all active research areas and form a major part of at least four regular international conference series.
Abstract: Paperback. The annealing of deformed materials is of both technological importance and scientific interest. The phenomena have been most widely studied in metals, although they occur in all crystalline materials such as the natural deformation of rocks and the processing of technical ceramics. Research is mainly driven by the requirements of industry, and where appropriate, the book discusses the extent to which we are able to formulate quantitative, physically-based models which can be applied to metal-forming processes.The subjects treated in this book are all active research areas, and form a major part of at least four regular international conference series. However, there have only been two monographs published in recent times on the subject of recrystallization, the latest nearly 20 years ago. Since that time, considerable advances have been made, both in our understanding of the subject and in the techniques available to the researcher.The
7,149 citations
TL;DR: In this article, a new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented, which considers the workpiece as a dissipator of power in the total processing system and evaluates the dissipated power co-contentJ = ∫o σ e ⋅dσ from the constitutive equation relating the strain rate (e) to the flow stress (σ).
Abstract: A new method of modeling material behavior which accounts for the dynamic metallurgical processes occurring during hot deformation is presented. The approach in this method is to consider the workpiece as a dissipator of power in the total processing system and to evaluate the dissipated power co-contentJ = ∫o σ e ⋅dσ from the constitutive equation relating the strain rate (e) to the flow stress (σ). The optimum processing conditions of temperature and strain rate are those corresponding to the maximum or peak inJ. It is shown thatJ is related to the strain-rate sensitivity (m) of the material and reaches a maximum value(J max) whenm = 1. The efficiency of the power dissipation(J/J max) through metallurgical processes is shown to be an index of the dynamic behavior of the material and is useful in obtaining a unique combination of temperature and strain rate for processing and also in delineating the regions of internal fracture. In this method of modeling, noa priori knowledge or evaluation of the atomistic mechanisms is required, and the method is effective even when more than one dissipation process occurs, which is particularly advantageous in the hot processing of commercial alloys having complex microstructures. This method has been applied to modeling of the behavior of Ti-6242 during hot forging. The behavior of α+ β andβ preform microstructures has been exam-ined, and the results show that the optimum condition for hot forging of these preforms is obtained at 927 °C (1200 K) and a strain rate of 1CT•3 s•1. Variations in the efficiency of dissipation with temperature and strain rate are correlated with the dynamic microstructural changes occurring in the material.
1,121 citations
15 Mar 2000-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the authors investigated new processing routes and new alloy chemistries for aircraft materials, which offer major improvements in ductility, toughness, fatigue performance and in reduction of residual stress in large dimension plate and sheet products.
Abstract: Driven by the increasing requirements from aircraft producers, Hoogovens Aluminium Rolled Products GmbH, together with Hoogovens Research & Development, has enhanced the property combinations of their aircraft materials. For these types of material, optimised processing routes as well as new alloy chemistries have been investigated. Whilst retaining the strength levels required by the aerospace industry, new processing routes offer major improvements in ductility, toughness, fatigue performance and in reduction of residual stress in large dimension plate and sheet products. A further goal of investigating new alloy chemistries is the trend towards new joining techniques such as welding and brazing for aircraft structures. These new joining techniques require different property combinations compared to the conventional aerospace alloys. In parallel to these improved processing routes and new alloy developments, new ultrasonic inspection techniques have been developed, which are able to predict fatigue performance and residual stress in thick plate products.
990 citations
TL;DR: Bulk metal working processes are carried out at elevated temperatures where the occurrence of simultaneous softening processes would enable the imposition of large strains in a single step or multi-step process.
Abstract: Bulk metal working processes are carried out at elevated temperatures where the occurrence of simultaneous softening processes would enable the imposition of large strains in a single step or multi...
622 citations
TL;DR: In the last two decades, processing maps have been developed on a wide variety of materials including metals and alloys, metal matrix composites, and aluminides, and applied to optimizing hot workability of materials and for process design in bulk metal working as discussed by the authors.
Abstract: In the last two decades, processing maps have been developed on a wide variety of materials including metals and alloys, metal matrix composites, and aluminides, and applied to optimizing hot workability of materials and for process design in bulk metal working. Processing maps consist of a superimposition of efficiency of power dissipation and the instability maps, the former revealing the "safe" domain for processing and the latter setting the limits for avoiding undesirable microstructures. The dynamic materials model, which forms the basis for processing maps, is discussed in relation to other materials models. The application of dynamical systems principles to understanding of deterministic chaos in the system will help in achieving a greater degree of microstructural control during processing. The patterns in the hot working behavior as revealed by the processing maps of several classes of alloys relevant to technology are reviewed briefly. Processing maps have also been applied to analyze several industrial problems including process optimization, product property control, and defect avoidance, and a few examples are listed. With the processing maps reaching a matured stage as an effective tool for optimizing materials workability, expert systems and artificial neural network models are being developed to aid and prompt novice engineers to design and optimize metal processing without the immediate availability of a domain expert, and the directions of research in this area are outlined.
353 citations