Effect of Process Parameters on Microstructures of 7055 Aluminum Alloy in Creep Age Forming

The effects of process parameters on evolution of microstructures of 7055 aluminum alloy in creep age forming were studied and the microstrucures were analyzed using transmission electron microscopy (TEM). Some important results are obtained: with the increasing of ageing time, the size of platelet shaped (known as Guinier-Preston (G-P) zones) precipitates and spherical shaped η' precipitates increased, the number of platelet shaped precipitates increased too, while the number of η' precipitates decreased; the precipitates with almost the same size distributed continuously and uniformly along the grain boundary with quite narrow precipitate free zones (PFZs) at 5 hours of ageing time, when the ageing time increases to 8 hours, the distribution of the precipitates along the grain boundary becomes discontinuous and the PFZs gets wider, while with the further increasing of the ageing time, the precipitates distributed continuously again along the grain boundary and the PFZs become more wider. From comparison of stress-aged alloy to stress-free-aged alloy, it was found that after 20 hours ageing, the precipitates in the stress-aged alloy are slightly coarser and the PFZs are wider, the density of retained η' is lower with the development of η phase.

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Techniques for Transmission Electron Microscopy of Fiber-Matrix Interfaces in Aluminum Alloy-Boron Composites by Ion Erosio

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065079 ◽

1971 ◽

Vol 29 ◽

pp. 204-205

Author(s):

G. G. Shaw

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Aluminum Alloy ◽

Electron Beam ◽

Pure Aluminum ◽

Ion Milling ◽

Transmission Electron ◽

Fiber Matrix ◽

Ion Erosion ◽

Row Of Fibers

The morphology and composition of the fiber-matrix interface can best be studied by transmission electron microscopy and electron diffraction. For some composites satisfactory samples can be prepared by electropolishing. For others such as aluminum alloy-boron composites ion erosion is necessary.When one wishes to examine a specimen with the electron beam perpendicular to the fiber, preparation is as follows: A 1/8 in. disk is cut from the sample with a cylindrical tool by spark machining. Thin slices, 5 mils thick, containing one row of fibers, are then, spark-machined from the disk. After spark machining, the slice is carefully polished with diamond paste until the row of fibers is exposed on each side, as shown in Figure 1.In the case where examination is desired with the electron beam parallel to the fiber, preparation is as follows: Experimental composites are usually 50 mils or less in thickness so an auxiliary holder is necessary during ion milling and for easy transfer to the electron microscope. This holder is pure aluminum sheet, 3 mils thick.

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High-Resolution Transmission Electron Microscopy Studies of a Near Sigma11 Grain Boundary in alpha-Alumina

Journal of the American Ceramic Society ◽

10.1111/j.1151-2916.1994.tb07001.x ◽

1994 ◽

Vol 77 (2) ◽

pp. 339-348 ◽

Cited By ~ 64

Author(s):

Thomas Hoche ◽

Philip R. Kenway ◽

Hans-Joachim Kleebe ◽

Manfred Ruhle ◽

Patricia A. Morris

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Transmission Electron ◽

Alpha Alumina

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Motion of Crystal/Crystal and Crystal/Amorphous Interfaces

MRS Proceedings ◽

10.1557/proc-183-79 ◽

1990 ◽

Vol 183 ◽

Author(s):

J. L. Batstone

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Temperature ◽

Grain Boundary ◽

Boundary Motion ◽

High Temperature Annealing ◽

Thermally Activated ◽

Transmission Electron ◽

Grain Boundary Motion

AbstractMotion of ordered twin/matrix interfaces in films of silicon on sapphire occurs during high temperature annealing. This process is shown to be thermally activated and is analogous to grain boundary motion. Motion of amorphous/crystalline interfaces occurs during recrystallization of CoSi2 and NiSi2 from the amorphous phase. In-situ transmission electron microscopy has revealed details of the growth kinetics and interfacial roughness.

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Microstructural Studies of High Coercivity Nd15Fe77B8 Sintered Magnets

MRS Proceedings ◽

10.1557/proc-96-193 ◽

1987 ◽

Vol 96 ◽

Cited By ~ 3

Author(s):

M. H. Ghandehari ◽

J. Fidler

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Electron Microprobe ◽

Boundary Phase ◽

High Coercivity ◽

Transmission Electron ◽

Microstructural Studies ◽

Domain Reversal

ABSTRACTMicrostructures of Nd15−xDyxFe77B8 prepared by alloying with Dy, and by using Dy2O3 as a sinl'ken adidive, have been determined using electron microprobe and transmission electron microscopy. The results have shown a higher Dy concentration near the grain boundaries of the 2–14–1 phase for magnets doped with Dy2O 3, as compared to the Dy-alloyed magnets. A two-step post sintering heat treatment was also studied for the two systems. The resultant concentration gradient of Dy in the 2–14–1 phase of the oxide-doped magnets is explained by the reaction of Dy2O3 with the Nd-rich grain boundary phase and its slow diffusion into thg 4–14–1 phase. Increased Dy concentration near the grain boundary is more effective in improving the coercivity, as domain reversal nucleation originates at or near this region.

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Localized dissolution of grain boundary T1 precipitates in Al-3Cu-2Li

Corrosion Reviews ◽

10.1515/corrrev-2015-0032 ◽

2015 ◽

Vol 33 (6) ◽

pp. 395-401 ◽

Cited By ~ 3

Author(s):

Ramasis Goswami

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Orientation Relationship ◽

S Phase ◽

Dissolution Behavior ◽

Moist Air ◽

Orientation Relation ◽

Transmission Electron ◽

Relationship Of

AbstractTransmission electron microscopy (TEM) was employed to investigate the dissolution behavior of nanocrystalline grain boundary T1 precipitates in Al-3Cu-2Li. These grain boundary T1 plates exhibit an orientation relation with matrix, with the (1-11)α-Al parallel to (0001)T1 and [022]α-Al parallel to [10-10]T1, which is similar to the orientation relationship of T1 plates formed within grains. TEM studies showed that these grain boundary T1 plates react readily in moist air. As a result of the localized dissolution, the Cu-rich clusters form onto T1, which is consistent with the localized dissolution behavior observed in nanocrystalline S phase in Al-Cu-Mg.

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Analytical transmission electron microscopy study of grain boundary precipitates in an Fe–Ni–Mn maraging alloy

Materials Science and Engineering A ◽

10.1016/j.msea.2006.02.097 ◽

2006 ◽

Vol 438-440 ◽

pp. 288-291 ◽

Cited By ~ 16

Author(s):

S. Hossein Nedjad ◽

M. Nili Ahmadabadi ◽

R. Mahmudi ◽

T. Furuhara ◽

T. Maki

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Analytical Transmission Electron Microscopy ◽

Transmission Electron Microscopy Study ◽

Transmission Electron

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Effect of Ge-rich Si1−zGez Segregation on the Morphological Stability of NiSi1−uGeu Film Formed on Strained (001) Si0.8Ge0.2 Epilayer

MRS Proceedings ◽

10.1557/proc-810-c4.7 ◽

2004 ◽

Vol 810 ◽

Cited By ~ 1

Author(s):

H.B. Yao ◽

D.Z. Chi ◽

S. Tripathy ◽

S.Y. Chow ◽

W.D. Wang ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

High Resolution ◽

Grain Boundary ◽

Surface Morphology ◽

Morphological Stability ◽

Triple Junctions ◽

Cross Sectional ◽

Transmission Electron ◽

Segregation Process

ABSTRACTThe germanosilicidation of Ni on strained (001) Si0.8Ge0.2, particularly Ge segregation, grain boundary grooving, and surface morphology, during rapid thermal annealing (RTA) was studied. High-resolution cross-sectional transmission electron microscopy (HRXTEM) suggested that Ge-rich Si1−zGez segregation takes place preferentially at the germanosilicide/Si1−xGex interface, more specifically at the triple junctions between two adjacent NiSi1−uGeu grains and the underlying epi Si1−xGex, and it is accompanied with thermal grooving process. The segregation process accelerates the thermal grooving of NiSi1−uGeu grain boundaries at the interface. The segregation-accelerated grain boundary grooving has significant effect on the surface morphology of NiSi1−uGeu films in Ni-SiGe system.

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Research on the Second Phase of Spray Forming Al-8.5Fe-1.3V-1.7Si Aluminum Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.886.36 ◽

2014 ◽

Vol 886 ◽

pp. 36-40

Author(s):

Rong Hua Zhang ◽

Bao Hong Zhu ◽

Xiao Ping Zheng

Keyword(s):

Electron Microscopy ◽

Phase Transition ◽

Transmission Electron Microscopy ◽

Aluminum Alloy ◽

Room Temperature ◽

Spray Forming ◽

Heating Process ◽

Second Phase ◽

Transmission Electron ◽

Second Phases

Heat-resistant Al-8.5Fe-1.3V-1.7Si aluminum alloys were prepared by spray forming technique. The phase transition of deposited alloys from room temperature to 500°C was measured by Differential Scanning Calorimeter. The organization and the second phases of the alloys were observed and studied by transmission electron microscopy. The research results show that No endothermic peak appears in the deposited alloys during heating process, there is no phase transition occur in the alloy during the heating process from room temperature to 500°C. The deposited alloys mainly include α-Al and α-Al12(Fe,V)3Si phase. Under the transmission electron microscopy, there are also a small amount of slug, fan-shaped, needle-like, block, strip second phases, these phases are Al12Fe3Si, Al8Fe2Si, θ-Al13Fe4, Al9FeSi3, Al6Fe.

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Structure and Dissociation of 15° Tilt Boundaries in Germanium

MRS Proceedings ◽

10.1557/proc-25-299 ◽

1983 ◽

Vol 25 ◽

Cited By ~ 1

Author(s):

W. Skrotzki ◽

H. Wendt ◽

C. B. Carter ◽

D. L. Kohlstedt

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundary ◽

Czochralski Method ◽

Boundary Plane ◽

First Order ◽

Grain Boundary Plane ◽

Transmission Electron ◽

Theoretical Predictions ◽

Tilt Boundaries

ABSTRACTThe structure and dissociation of grain boundaries in Ge bicrystals, grown by the Czochralski method, have been analyzed by visible light and transmission electron microscopy. The seed crystals were oriented to yield either a symmetric or an asymmetric grain boundary plane with a 15° rotation about a common <110> direction. The asymmetric boundary, with a {111} boundary plane, dissociated along most of its length into a first order twin boundary (Σ 3) and a symmetric 55° grain boundary (Σ 41c). The symmetric 15° boundary is composed of an array of Lomer dislocations. Contrary to theoretical predictions, this boundary is stable.

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