Morphology and microstructure evolution of AlxGa1-xN epilayers grown on GaN/sapphire templates with AlN interlayers observed by transmission electron microscopy

2008 ◽  
Author(s):  
L. Lu ◽  
B. Shen ◽  
F.J. Xu ◽  
S. Huang ◽  
Z.L. Miao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microstructure Evolution ◽  
Transmission Electron

Microstructure Evolution of Hydrogenated Ti6Al4V Alloy during Compression

2012 ◽  
Vol 190-191 ◽  
pp. 517-521
Author(s):  
Bao Guo Yuan ◽  
Qiang Chen ◽  
Hai Ping Yu ◽  
Ping Li ◽  
Ke Min Xue ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Dislocation Density ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
True Strain ◽  
True Stress ◽  
Compression Tests ◽  
Transmission Electron ◽  
Good Repeatability

Compression tests of the hydrogenated Ti6Al4V0.2H alloy were carried out using an Instron 5569 machine at room temperature. True stress-strain curves of the hydrogenated Ti6Al4V0.2H alloy under different compressive strains were obtained. Microstructure evolution of the hydrogenated Ti6Al4V0.2H alloy during the process of compression was investigated by optical microscopy and transmission electron microscopy. Results show that true stress-true strain curves of Ti6Al4V0.2H alloy have good repeatability. The deformation of grains, the dislocation density and slipping evolution during the process of compression are discussed.

scholarly journals Microstructure Evolution in He-Implanted Si at 600 °C Followed by 1000 °C Annealing

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5107
Author(s):  
Zhen Yang ◽  
Zhiping Zou ◽  
Zeyang Zhang ◽  
Yubo Xing ◽  
Tao Wang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Single Crystal ◽  
Microstructure Evolution ◽  
Cavity Growth ◽  
Stacking Fault ◽  
Structural Defects ◽  
Dislocation Loops ◽  
Transmission Electron

Si single crystal was implanted with 230 keV He+ ions to a fluence of 5 × 1016/cm2 at 600 °C. The structural defects in Si implanted with He at 600 °C and then annealed at 1000 °C were investigated by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The microstructure of an as-implanted sample is provided for comparison. After annealing, rod-like defects were diminished, while tangled dislocations and large dislocation loops appeared. Dislocation lines trapped by cavities were directly observed. The cavities remained stable except for a transition of shape, from octahedron to tetrakaidecahedron. Stacking-fault tetrahedrons were found simultaneously. Cavity growth was independent of dislocations. The evolution of observed lattice defects is discussed.

Ultra-Fine Grained Fe-32%Ni Alloy Processed by Multi-Axial Forging

2010 ◽  
Vol 97-101 ◽  
pp. 187-190 ◽  
Author(s):  
Bao Jun Han
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Microstructure Evolution ◽  
Strain Path ◽  
Internal Stresses ◽  
Deformation Bands ◽  
Fine Grained ◽  
Transmission Electron ◽  
Ni Alloy ◽  
Equiaxed Grains

The Fe-32%Ni alloy was multi-axially forged at the temperature of 873K and strain rate of 10-2s-1, then the microstructure evolution in Fe-32%Ni alloy during deformation was investigated by the transmission electron microscopy (TEM). The results show that the grain size decreases with strain. The severe plastic deformed microstructure is characterized by the ultra-fine equiaxed grains and high internal stresses. The microstructure evolution mechanism is presented as the following: firstly, the dislocations accumulate as deformation bands in some directions with the progress of deformation; then the cellular structured subgrains are formed by continuous intersecting of deformation bands for the changing of strain path; eventually, the ultra-fine structured grains are formed by the subgrains rotation and the dislocations rearrangement.

scholarly journals Microstructure Evolution and Coarsening of θ′-Al2Cu Precipitates in a Creep Aged Al-Cu-Mn Alloy

2021 ◽  
Vol 2101 (1) ◽  
pp. 012071
Author(s):  
Soban Muddassir Dar ◽  
Yutao Zhao ◽  
Hengcheng Liao ◽  
Xizhou Kai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Rate ◽  
Microstructure Evolution ◽  
Average Length ◽  
Transmission Electron ◽  
Creep Exposure ◽  
Creep Temperature ◽  
Scanning Electron

Abstract This paper describes the microstructure evolution in a creep aged Al-Cu-Mn alloy using optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show the sub-grains formation and accelerated coarsening of θ′ precipitates in creep aged samples. It is observed that at an applied stress of 50MPa, as the creep temperature increases the average length of θ′ precipitates increases and their aspect ratio first increases then decreases. It is also found that after 100h of creep exposure at 200°C/50MPa, θ′ precipitates have grown to an average length of 279nm; at 225°C/50MPa to an average length of 425nm and at 250°C/50MPa they have grown to an average length of 844nm. Coarsening/growth rate of the precipitates is described by Lifshitz-Slyozov-Wagner (LSW) model.

A TEM Study of Bubbles Growth with Temperature in Xenon and Krypton Implanted Uranium Dioxide

2012 ◽  
Vol 323-325 ◽  
pp. 191-196 ◽  
Author(s):  
Amélie Michel ◽  
C. Sabathier ◽  
G. Carlot ◽  
M. Cabié ◽  
S. Bouffard ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Uranium Dioxide ◽  
Microstructure Evolution ◽  
Room Temperature ◽  
Number Density ◽  
Thin Foils ◽  
Transmission Electron ◽  
Growth Phenomenon ◽  
Increasing Temperature

Transmission electron microscopy (TEM) characterizations were carried out on a set of UO2 thin foils previously implanted at room temperature with 400 keV Xe2+ and 250 keV Kr2+ ions at the fluence 7.1015 at.cm-2 (equivalent to 1 at.%/at. UO2). The experiment was devoted to the study of the evolution of the fission gases bubbles populations with increasing temperature. Annealings were performed in the laboratory furnace at 600°C, 800°C, 1000°C for 12h, 1400°C for 4h and 1500°C for 2h under Ar-5%H2 atmosphere. For each annealing condition and for as-implanted specimens the bubble population has been characterized in size and number density. A comparison between Xe and Kr has been done that showed a similar behaviour. Globally, from the as-implanted sample to the 1500°C annealed, the bubbles growth phenomenon and the microstructure evolution with temperature was put in relieve.

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