scholarly journals Characterization of Precipitation in 7055 Aluminum Alloy by Laser Ultrasonics

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 275
Author(s):  
Zhenge Zhu ◽  
Hao Peng ◽  
Yacheng Xu ◽  
Xueyong Song ◽  
Jinrong Zuo ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Laser Ultrasonics ◽  
Precipitate Size ◽  
Destructive Testing ◽  
Laser Ultrasonic ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
7055 Aluminum Alloy ◽  
The Time Domain

After different rolling conditions, four 7055 aluminum alloy samples with different precipitation sizes were measured by scanning electron microscope, transmission electron microscope and laser ultrasonic. The attenuation coefficients of ultrasound measured by laser ultrasonic were calculated in the time domain, frequency domain and wavelet denoising, respectively. The relationship between the precipitate size and attenuation coefficient was established. The results show that the attenuation of the ultrasonic wave is related to the size of the precipitated phase; this provides a new method for rapid non-destructive testing of the precipitation of aluminum alloys.

Microstructural Characterization of an Al-Mg-Si Aluminum Alloy Processed by Equal Channel Angular Pressing

2013 ◽  
Vol 745-746 ◽  
pp. 303-308
Author(s):  
Zhen Zhang ◽  
Man Ping Liu ◽  
Ying Da Yu ◽  
Pål C. Skaret ◽  
Hans Jørgen Roven
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
High Resolution ◽  
Dislocation Density ◽  
Equal Channel Angular Pressing ◽  
Transmission Electron Microscope ◽  
Microstructural Characterization ◽  
Dark Field ◽  
Angular Pressing ◽  
Transmission Electron

In the present work, a peak-aged 6061 Al-Mg-Si aluminum alloy was subjected to equal channel angular pressing (ECAP) at 110 °C. The microstructure of the sample was characterized by high-resolution transmission electron microscope and weak-beam dark-field method. It was shown that the dislocation density in some local areas is much lower than the average dislocation density expected in the usual alloys processed by severe plastic deformation. High-resolution transmission electron microscope observations indicated that many full dislocations were dissociated into partial dislocations connected by stacking faults. In addition, a Z-shaped defect (i.e., a type of dislocation locks) probably formed by the reactions of the partials in different {111} planes was first observed in the ECAPed alloy. Furthermore, the precipitation behavior and sequence in the present ECAPed sample were identified by high-resolution transmission electron microscopy.

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

2011 ◽  
Vol 80-81 ◽  
pp. 40-45 ◽  
Author(s):  
Li Hua Zhan ◽  
Yan Guang Li ◽  
Ming Hui Huang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloy ◽  
Grain Boundary ◽  
Process Parameters ◽  
Ageing Time ◽  
Aged Alloy ◽  
Transmission Electron ◽  
7055 Aluminum Alloy ◽  
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.

Exfoliation Corrosion Behavior of 2524 Aluminum Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1159-1162 ◽  
Author(s):  
Sheng Yang ◽  
Dan Qing Yi ◽  
Su Juan Yao ◽  
Ya Ping Hou
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Hydrogen Evolution ◽  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Exfoliation Corrosion ◽  
Corrosion Kinetics ◽  
Transmission Electron

The exfoliation corrosion behavior of 2524 aluminum alloy was studied by Transmission Electron Microscope (TEM), hydrogen evolution and Electrochemical impedance spectroscopy (EIS) . The results showed that 2524 aluminum alloy was very susceptible to exfoliation corrosion and the exfoliation corrosion appeared after 24 h. EIS could better explain the exfoliation corrosion than hydrogen evolution. Exfoliation corrosion kinetics included accelerated formation of pitting, quick development of pitting, retarded formation of exfoliation and steady development of exfoliation.

Effects of Biaxial Pre-Stretching on Microstructures and Mechanical Properties of 2024 Aluminum Alloy Thin Plates

2014 ◽  
Vol 472 ◽  
pp. 607-611 ◽  
Author(s):  
Jian Jun Wu ◽  
Rui Chao Guo ◽  
Hao Li ◽  
Shen Zhang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Electron Microscope ◽  
Plane Strain ◽  
Transmission Electron Microscope ◽  
Strain State ◽  
Thin Plates ◽  
2024 Aluminum Alloy ◽  
Transmission Electron

Biaxial pre-stretching is implemented by bulge forming model. After engraved circular grids on new quenching blank, the specimen is biaxially pre-stretching formed. We use JGX-2 Engineering Microscope to measure principal pre-stretching points with 1.5%-3.1% elongation, which are in plane strain state. Hardness is measured by GYZJ 934-1 type Barcol Hardness and microstructures are observed by JEM-200CX Transmission Electron Microscope. The result shows that the influence on tensile strength of biaxial pre-stretching for new quenching state specimen is not big; however, it is the principal pre-stretching quantity 1.75% that improves microstructure and hardness.

Microstructure of 7N01 Aluminum Alloy Microalloyed with Er and Zr in the Homogenization Process

2020 ◽  
Vol 993 ◽  
pp. 123-129
Author(s):  
Pei Hao Zhao ◽  
Xiao Lan Wu ◽  
Kun Yuan Gao ◽  
Yu Sheng Ding ◽  
Hui Huang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Electron Microscope ◽  
Cast Alloy ◽  
Secondary Phase ◽  
Dendritic Segregation ◽  
Secondary Phases ◽  
Sem Images ◽  
Homogenization Process ◽  
Transmission Electron ◽  
Before And After

The microstructure and segregation of 7N01 aluminum alloy microalloyed with Er and Zr before and after homogenization process at 470 °C for 24 h have been investigated using transmission electron microscope (TEM), and scanning electron microscope (SEM) equipped with energy dispersive X-ray spectroscope (EDS) and transmission electron detecter (STEM). SEM images and EDS line scan results showed that there were dendritic segregation of Mg and Zn and micron-sized primary phases along dendrites in the as-cast alloy. The primary phases were mainly Al2Mg3Zn3 containing Al, Zn, Mg and Mn. And a small amount of primary phases were the particles containing Al, Zn, Mg, Mn, Cr and Er and the particles containing Al, Zn, Mg, Er, Mn, Fe and Cr. After homogenization at 470°C for 24 h, dendritic segregation of Mg and Zn was eliminated, Al2Mg3Zn3 and the particles containing Al, Zn, Mg and Mn were basically dissolved. The particles containing Al, Zn, Mg, Mn, Cr and Er and the particles containing Al, Zn, Mg, Er, Mn, Fe and Cr remained. Meanwhile, TEM and STEM images showed that a large number of secondary phases appeared after the homogenization, which were mainly distributed in the inter-dendrite area. EDS results showed that the block-shaped and rod-shaped phases with the width of 10-70 nm and length of 100-500 nm were the particles containing Al, Cr and Mn or Al, Mg, Cr and Mn, and the ellipsoid secondary phase with the size of 50-100 nm was MgZn2.

Effect of Addition Zr on As-Homogenization Microstructures of 5182 Aluminum Alloy

2013 ◽  
Vol 749 ◽  
pp. 47-53 ◽  
Author(s):  
Bin Hui Jin ◽  
Bao Hong Zhu ◽  
Xi Wu Li
Keyword(s):  
Heat Treatment ◽  
Aluminum Alloy ◽  
Electron Microscope ◽  
Optimum Condition ◽  
Intermetallic Compounds ◽  
Dendritic Structure ◽  
Optical Microscope ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The microstructure of 5182 alloys, standard and modified by Zr, before/after homogenizing heat treatment were investigated by optical microscope (OM), scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and transmission electron microscope (TEM). The microstructures on optimum condition for homogenizing heat treatment and the effect of Zr were discussed. It is found that the intermetallic compounds formed on the grain boundaries are less in Zr modified 5182 than 5182 alloys for the as-cast structure. After the two alloys homogenized at 475 for 24h, the dendritic structure disappear and intermetallic compounds become discontinuous, Al2Mg3 phases are decomposed, and there are some precipitates of Al6(Mn,Fe) and Al6Mn in the grain interior. In addition, precipitates of Al3Zr distributed in the matrix of Zr modified 5182 alloys.

scholarly journals Effects of Prebending Radii on Microstructure and Fatigue Performance of Al-Zn-Mg-Cu Aluminum Alloy after Creep Age Forming

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 630 ◽  
Author(s):  
Dalian Yang ◽  
Jingjing Miao ◽  
Fanyu Zhang ◽  
Zhuo Fu ◽  
Yilun Liu
Keyword(s):  
Aluminum Alloy ◽  
High Cycle Fatigue ◽  
Fatigue Performance ◽  
7075 Aluminum Alloy ◽  
Cycle Fatigue ◽  
Free Zone ◽  
Precipitated Phase ◽  
Transmission Electron ◽  
Creep Age Forming ◽  
Scanning Electron

A series of creep age forming experiments were carried out on 7075 aluminum alloy with different prebending radii at 443 K for 10 h. The hardness, tensile properties and high cycle fatigue performance of the alloy after creep age forming were obtained. In addition, the microstructure and fatigue fracture of the alloy were observed by transmission electron microscopy (TEM) and scanning electron microscope (SEM). The results show that with the increase of the prebending radius, the hardness, strength and elongation of the alloy increased; meanwhile, the conditional fatigue limit increased, the size of precipitated phase decreased and the quantity increased, while the width of precipitate free zone decreased.

A Reproducible Selective Stain for Cardiac Sarcoplasmic Reticulum

1974 ◽  
Vol 32 ◽  
pp. 214-215
Author(s):  
R. A. Waugh ◽  
J. R. Sommer
Keyword(s):  
Complex System ◽  
Electron Microscope ◽  
Sarcoplasmic Reticulum ◽  
Transmission Electron Microscope ◽  
Electron Microscopic ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Transmission Electron

Cardiac sarcoplasmic reticulum (SR) is a complex system of intracellular tubules that, due to their small size and juxtaposition to such electron-dense structures as mitochondria and myofibrils, are often inconspicuous in conventionally prepared electron microscopic material. This study reports a method with which the SR is selectively “stained” which facilitates visualizationwith the transmission electron microscope.

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

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.

Surface Structure of the Spores of Glugea Weissenbergi

1969 ◽  
Vol 27 ◽  
pp. 238-239
Author(s):  
Sanford H. Vernick ◽  
Anastasios Tousimis ◽  
Victor Sprague
Keyword(s):  
Electron Microscope ◽  
Surface Structure ◽  
Transmission Electron Microscope ◽  
Mature Spore ◽  
Spore Surface ◽  
Sectioned Material ◽  
Transmission Electron ◽  
Surface Detail

Recent electron microscope studies have greatly expanded our knowledge of the structure of the Microsporida, particularly of the developing and mature spore. Since these studies involved mainly sectioned material, they have revealed much internal detail of the spores but relatively little surface detail. This report concerns observations on the spore surface by means of the transmission electron microscope.

Sign in / Sign up

Export Citation Format

Share Document