Estimation of Crystalline Size of Deformed 5251 Al Alloy Using PALT and XRD Techniques

2013 ◽  
Vol 337-338 ◽  
pp. 11-18
Author(s):  
M. Abdel-Rahman ◽  
Ahmed G. Attallah ◽  
M. El-Sayed ◽  
A.A. Ibrahim ◽  
A.A. Akel ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Al Alloys ◽  
Radioactive Isotopes ◽  
Crystalline Size ◽  
Al Alloy ◽  
Solid Materials ◽  
Deformation Effect ◽  
Powerful Technique ◽  
Xrd Techniques

Certain radioactive isotopes decay by emitting positrons, and the positrons can be used to probe the structure of solid materials. For example, one can investigate the grain size due to deformation in a metal. XRD is also a powerful technique for detection the defects introduced into a metal and for investigating the microstructure of a deformed metal. In this paper we shall investigate the plastic deformation effect on the grain size of 5251 Al alloys using two different techniques, PALT and XRD. The study shows a significant effect of the plastic deformation on the grain size which decreases as the deformation increases.

Ductile deformation and microstructures

2021 ◽  
pp. 58-85
Author(s):  
Jean-Luc Bouchez ◽  
Adolphe Nicolas
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Elastic Deformation ◽  
Applied Stress ◽  
Deformation Mechanism ◽  
Chemical Elements ◽  
Shear Zones ◽  
Ductile Deformation ◽  
Deformation Mechanisms ◽  
Solid Materials

In contrast to the elastic deformation, which is reversible, usually neglected by field geologists but important for geophysicists working in seismology, ductile deformation is irreversible. This chapter is restricted to solid materials. Materials containing a melt fraction will be examined in Chapter 7. In the geological literature, ‘ductile’ is often used as a synonym for ‘plastic’. The latter is rather used, and will be used to specify deformation mechanisms that dominantly involve the action of dislocations. In contrast to brittle deformation, which by essence is discontinuous and highly localized (see Chapter 3), ductile deformation is generally continuous and affects large volumes of rock. However, ductile deformation may be concentrated into restricted rock volumes (or domains). Such localization is common in shear zones and/or when superplastic deformation mechanism is involved. Plastic deformation mechanisms naturally depend on temperature, magnitude of the applied stress, mineral nature and grain-size of the rocks. In upper parts of the crust, fluids are able to carry chemical elements over large distances and influence the deformation mechanisms. Micrographs of several microstructural types as well as deformation maps for olivine and calcite are given at the end of this chapter.

Structural Characterization of FeAl28Cr5 Alloy Deformed in the Hot Torsion Process

2016 ◽  
Vol 246 ◽  
pp. 43-46 ◽  
Author(s):  
Iwona Bednarczyk ◽  
Magdalena Jabłońska
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Structural Changes ◽  
Al Alloys ◽  
Dynamic Processes ◽  
Fine Grained ◽  
Average Grain Size ◽  
Fine Grained Structure ◽  
Hot Torsion

Current research in the field of iron aluminides are directed towards to understand the structural phenomena occurring during plastic deformation of these alloys. The obtained results of the study and collected informations will be used to determine the description of the structural changes taking place during hot deformation of Fe ̶Al alloys. The article presents the results of the study of the alloy FeAl28Cr5 deformed by hot torsion in temperature range of 800÷1100°C and a strain rate of 0.1 s-1. The analysis of the structure of the alloy FeAl28Cr5 allowed to reveal changes caused by dynamic processes of deformation. The results of torsion tests show the possibility to obtain a fine-grained structure with of parameters of the processes (T=1000°C, 1100°C) and strain of ε=40. After deformation at strain of (ε=40) the structure consists of fine grains with a misorientation angle higher than 15°, and the average grain size diameter D=28.5 micrometers. Deformation at a temperature of T=1000°C and 1100°C is accompanied by superplastic flow effect.

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.

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.

High temperature creep strength in a nanodispersion-strengthened ferritic alloy prepared by heavy plastic deformation

2011 ◽  
Vol 1298 ◽  
Author(s):  
David G. Morris ◽  
Maria Antonia Muñoz-Morris
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
High Temperature ◽  
Creep Strength ◽  
High Strain ◽  
Ferritic Steels ◽  
Al Alloy ◽  
Second Phase ◽  
Corrosion Properties ◽  
Wide Range

ABSTRACTProcesses of severe plastic deformation have been investigated for a wide range of ductile alloys over the past decade, generally with an objective of refining the microstructural scale, for example the grain size, but have hardly been considered for intermetallics. This presentation discusses processing of a boride-containing Fe3Al alloy using a multidirectional, high-strain and high-temperature forging technique. Iron aluminides with relatively low Al contents can be regarded as Al-rich ferritic steels with outstanding oxidation-corrosion properties. However, as for many ferritic steels, they show poor creep resistance at temperatures above about 600ºC. The deformation processing leads to a material with large grain size and refined dispersion of thermally-stable boride particles. The particles produce a large increase in creep strength under conditions of moderate stresses and low strain rates at temperatures near 700ºC. This high-strain forging technique can be seen as an intermediate processing method between conventional wrought metallurgy and mechanical-alloying powder metallurgy, whereby an initially coarse and inhomogeneous dispersion of second phase is refined and made more homogeneous, and can be considered as a useful processing technique for a wide range of particle-containing materials.

Influence of SiC Particles on the Grain Refinement of an Mg-Al Alloy

2009 ◽  
Vol 618-619 ◽  
pp. 445-448 ◽  
Author(s):  
Andreas Schiffl ◽  
Mark Easton
Keyword(s):  
Grain Size ◽  
Phase Equilibria ◽  
Grain Refinement ◽  
Al Alloys ◽  
Al Alloy ◽  
Grain Refiner ◽  
Sic Particles ◽  
Ternary Carbides

SiC particles are effective grain refiners in Mg-Al alloys. Several investigations, from different researchers, into their effect on a range of alloys with different Al contents has been undertaken and it has been found that the greatest reduction in grain size occurs in alloys having low Al contents. Performing grain refinement studies on a range of alloy contents also allows for further investigation into the mechanisms of grain refinement. It was found that the size of the SiC particles is also important in magnesium grain refinement. However, the presence of Mg2Si in the microstructure and the consideration of phase equilibria suggest that SiC can transform into other binary or ternary carbides. If such carbides are formed, they may also act as an effective grain refiner for Mg-Al alloys. In this study, the possibility of formation of new carbides (Al4C3, Al2MgC2, Mn7C3, Mg2C, Mg2C3, Al2CO etc.) and their ability to be good grain refiners for Mg-Al alloys is discussed.

Application of High-Strain-Rate Superplastic Zn-Al Alloy to Seismic Dampers and its Optimised Shape Design

2007 ◽  
Vol 551-552 ◽  
pp. 583-590 ◽  
Author(s):  
Atsumichi Kushibe ◽  
Yorinobu Takigawa ◽  
Kenji Higashi ◽  
Kazuo Aoki ◽  
Koichi Makii ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Work Hardening ◽  
Tall Buildings ◽  
High Energy ◽  
Local Deformation ◽  
Al Alloys ◽  
Optimum Shape ◽  
Al Alloy ◽  
Seismic Damper ◽  
Damping Material

As a new damping material, the authors first developed a Zn-22wt.%-Al eutectoid alloy with ultra-fine grains exhibiting superplasticity at room temperature by means of thermomechanical controlling processes (TMCPs). The Zn-Al alloy has a few advantages such as low work-hardening rate and high ductility over a conventional seismic damping material, for instance, a low-yield-point steel. In addition, Zn-Al alloys are environment-conscious because of no harmful metal like Pb. However, when Zn-Al alloys are subjected to plastic deformation, since its work hardening is small, plastic deformation proceeds locally so that required absorption energy cannot be sufficiently obtained, and local fracture and local deformation instability can take place easily, which is the intrinsic characteristic of superplastic materials. Therefore we attempted to develop a shear panel type, a brace type damper for tall buildings and a bending type damper for Japanese wooden houses using FEM analysis in order to minimize localized strain and local deformation and to determine the optimum shape for this Zn-Al superplastic seismic damper. As a result, an ecological and high-energy absorption seismic dampers, so-called “maintenance-free seismic damper,” was successfully developed.

Continuous Amorphization of Zr-Based Alloys by Controlled Mechanical Intermixing

1998 ◽  
Vol 554 ◽  
Author(s):  
G. Wilde ◽  
H. Sieber ◽  
J. H. Perepezko
Keyword(s):  
Grain Size ◽  
Solid State ◽  
Critical Value ◽  
Glass Forming Ability ◽  
Al Alloys ◽  
Al Alloy ◽  
Mechanical Working ◽  
Glass Forming ◽  
Ni Alloys ◽  
State Amorphization

AbstractBinary Zr-(Cu, Ni, Al) alloys were mechanically intermixed by cold-rolling stacks of elemental foils. The results indicate that solid-state amorphization is initiated if the grain size of the Zr-Cu and Zr-Ni alloys falls below a critical value. Amorphization was not observed for the Zr-Al alloy. These results are in accordance to the predictions of a model for solid-state amorphization. The comparison with the results on a quaternary Zr-Cu-Ni-Al alloy indicate the influence of multicomponent alloying on the glass-forming ability of Zr-rich alloys by mechanical working.

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.

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