Dynamic aging in an Fe–Ni–Al alloy upon megaplastic deformation. Effect of the temperature and deformation rate

A final thermomechanical treatment (FTMT) including peak aging and subsequent dynamic aging was proposed to prepare 7055 Al alloy sheets. The optimization was based on nine well-planned orthogonal experiments. Three main processing conditions in the thermomechanical treatment for obtaining the optimum synthetic properties of 7055 (i.e. preheating temperature, final rolling temperature and deformation degree) were investigated. It was shown that the final rolling temperature is the most important factor among the three parameters, and the optimum properties (yield strength: 651 MPa, ultimate tensile strength: 660 MPa) of 7055 Al alloy sheet can be gained with preheating at 140oC and 40% deformation at 170oC. With dynamic aging, grain boundary precipitates became discontinuous without much coarsening of matrix precipitates, while they were continuously distributed after T6 aging. The present optimal FTMT process can improve the intergranular / exfoliation corrosion resistance without sacrificing the strength compared to T6 tempering. The present FTMT process as a good alternative can produce high-strength Al alloy sheets with high strength and good corrosion resistance efficiently and economically.

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

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.337-338.11 ◽

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.

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Unusual Microstructures and Strength Characteristics of Cu/Ti3AlC2 Cermets

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.1394 ◽

2007 ◽

Vol 336-338 ◽

pp. 1394-1396 ◽

Cited By ~ 10

Author(s):

Hong Xiang Zhai ◽

Ming Xing Ai ◽

Zhen Ying Huang ◽

Yang Zhou ◽

Shi Bo Li ◽

...

Keyword(s):

Fracture Strength ◽

Volume Content ◽

Deformation Rate ◽

Strength Characteristics ◽

Al Alloy ◽

Fracture Face ◽

Three Point Bending ◽

Copper Powders ◽

Network Feature ◽

Interface Bond

Cu/Ti3AlC2 cermets prepared by pressless sintering a mixture of Ti3AlC2 and copper powders were investigated. It was found that the Cu/Ti3AlC2 possesses an unusual microstructure made up of sub-micro-sheet layered Ti3C2 and Cu-Al alloy within one Ti3AlC2 particulate. The fracture strength measured by the three-point-bending manner is increased but the deformation rate is reduced with increase in the volume content of Ti3AlC2 from 30 % to 90 %. The highest fracture strength reached to as higher as 983.9 MPa, corresponding to an extreme strain of 2.64 %. The fracture in mode was changed from brittle to ductile with reduce in the content of Ti3AlC2. The higher fracture strength can be attributed to a stronger interface bond between Ti3AlC2 and Cu-Al phase. A significant network feature formed by the Cu-Al alloy surrounding Ti3AlC2 particulates was observed from the fracture face.

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Microstructure and mechanical properties of Ti–40 mass % Nb alloy after megaplastic deformation effect

10.1063/1.4932896 ◽

2015 ◽

Cited By ~ 1

Author(s):

Yurii P. Sharkeev ◽

Anna Yu. Eroshenko ◽

Ivan A. Glukhov ◽

Zeming Sun ◽

Qifang Zhu ◽

...

Keyword(s):

Mechanical Properties ◽

Deformation Effect ◽

Microstructure And Mechanical Properties ◽

Megaplastic Deformation

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Influence of Prestraining, Deformation Rate and Temperature on Elasto-Viscoplasticity and Dynamic-Aging of Metal Materials (The Study of SUS316L Stainless Steel at Temperature Range from -35 to 150.DEG.C.)

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series A ◽

10.1299/kikaia.70.763 ◽

2004 ◽

Vol 70 (693) ◽

pp. 763-770

Author(s):

Takanobu OYAMADA ◽

Kenji KANEKO ◽

Naoya TOYOSHIMA ◽

Daisuke SHIMIZU

Keyword(s):

Stainless Steel ◽

Deformation Rate ◽

Temperature Range ◽

Dynamic Aging ◽

Metal Materials

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Effets of surfaces on precipitate morphology in irradiated thin foils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110416 ◽

1978 ◽

Vol 36 (1) ◽

pp. 654-655

Author(s):

D.I. Potter ◽

A. Taylor

Keyword(s):

Ion Irradiation ◽

Dark Field Image ◽

Thin Foil ◽

Dark Field ◽

Al Alloy ◽

Bright Field Image ◽

Dislocation Loops ◽

Precipitate Morphology ◽

Thin Foils

Thermal aging of Ni-12.8 at. % A1 and Ni-12.7 at. % Si produces spatially homogeneous dispersions of cuboidal γ'-Ni3Al or Ni3Si precipitate particles arrayed in the Ni solid solution. We have used 3.5-MeV 58Ni+ ion irradiation to examine the effect of irradiation during precipitation on precipitate morphology and distribution. The nearness of free surfaces produced unusual morphologies in foils thinned prior to irradiation. These thin-foil effects will be important during in-situ investigations of precipitation in the HVEM. The thin foil results can be interpreted in terms of observations from bulk irradiations which are described first.Figure 1a is a dark field image of the γ' precipitate 5000 Å beneath the surface(∿1200 Å short of peak damage) of the Ni-Al alloy irradiated in bulk form. The inhomogeneous spatial distribution of γ' results from the presence of voids and dislocation loops which can be seen in the bright field image of the same area, Fig. 1b.

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A microscopic marker experiment study on high temperature oxidation of Ni-Al alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144085 ◽

1986 ◽

Vol 44 ◽

pp. 514-515

Author(s):

Shou-kong Fan

Keyword(s):

Transport Mechanism ◽

High Temperature Oxidation ◽

Transverse Section ◽

Al Alloy ◽

Metal Interface ◽

Electron Microscopic ◽

Temperature Oxidation ◽

Analytical Electron ◽

Microscopic Studies ◽

First Time

Transmission and analytical electron microscopic studies of scale microstructures and microscopic marker experiments have been carried out in order to determine the transport mechanism in the oxidation of Ni-Al alloy. According to the classical theory, the oxidation of nickel takes place by transport of Ni cations across the scale forming new oxide at the scale/gas interface. Any markers deposited on the Ni surface are expected to remain at the scale/metal interface after oxidation. This investigation using TEM transverse section techniques and deposited microscopic markers shows a different result,which indicates that a considerable amount of oxygen was transported inward. This is the first time that such fine-scale markers have been coupled with high resolution characterization instruments such as TEM/STEM to provide detailed information about evolution of oxide scale microstructure.

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Diffraction study on bainite of Cu-Al alloy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178161 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1006-1007

Author(s):

Delu Liu ◽

T. Ko

Keyword(s):

Diffraction Study ◽

Parent Phase ◽

Al Alloy ◽

Alloy Sample ◽

Bright Field Image ◽

Hexagonal System ◽

Iced Brine ◽

Diffraction Patterns ◽

Zone Pattern ◽

Stacking Structure

Structure of bainite in Cu-Al and Cu-Zn-Al alloys has been reported as 3R, 9R or 18R long period stacking structure (LPS) by X-ray and electron diffraction studies. In the present work, a Cu-25.5 (at)% Al alloy sample was heated at 900°C for 2 h then isothermally held at 450°C for 60 s before quenching into iced brine. FIG.1 shows a TEM bright field image of bainite plates (marked B) grown from grain boundary. The parent phase ( with DO3 structure ) has transformed to martensite (marked M ) during cooling from 450° C to 0°C. Both bainite and martensite plates have dense striations inside.Careful diffraction study on a JEOL 2000FX TEM with accelerating voltage 200 KV revealed (FIG.2) that the diffraction patterns contai_ning the same zone axis [001] ( hexagonal index ) or [111]c ( cubic index ) are from a bainite plate with obtuse V-shape. They are indexed as [010], [140], [130], [120], [230], [340] and [110] zone pattern for hexagonal system respectively.

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