Deformation dynamics and pre-compression effects on Mg-3Al-1Zn alloy: An in situ synchrotron-based multiscale study

2021 ◽  
pp. 111349
Author(s):  
N.B. Zhang ◽  
S.H. Guo ◽  
X.H. Gong ◽  
Y.Y. Zhang ◽  
S. Chen ◽  
...  
Keyword(s):  
Deformation Dynamics ◽  
Compression Effects

scholarly journals Comparing Cyclic Tension-Compression Effects on CoCrFeMnNi High-Entropy Alloy and Ni-Based Superalloy

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 420 ◽  
Author(s):  
Tu-Ngoc Lam ◽  
You-Shiun Chou ◽  
Yao-Jen Chang ◽  
Tsung-Ruei Sui ◽  
An-Chou Yeh ◽  
...  
Keyword(s):  
Lattice Strain ◽  
Cyclic Hardening ◽  
High Entropy Alloy ◽  
Face Centered Cubic ◽  
High Entropy ◽  
Nickel Based Superalloy ◽  
Face Centered ◽  
Compression Effects ◽  
In Situ Neutron Diffraction

An equal-molar CoCrFeMnNi, face-centered-cubic (fcc) high-entropy alloy (HEA) and a nickel-based superalloy are studied using in situ neutron diffraction experiments. With continuous measurements, the evolution of diffraction peaks is collected for microscopic lattice strain analyses. Cyclic hardening and softening are found in both metallic systems. However, as obtained from the diffraction-peak-width evolution, the underneath deformation mechanisms are quite different. The CoCrFeMnNi HEA exhibits distinct lattice strain and microstructure responses under tension-compression cyclic loadings.

scholarly journals In SituAtomistic Deformation Mechanisms Study of Nanowires

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Yonghai Yue ◽  
Qihua Gong ◽  
Qi Zhang
Keyword(s):  
Scientific Progress ◽  
Structural Evolution ◽  
High Strength ◽  
Research Field ◽  
Atomic Scale ◽  
Experimental Mechanics ◽  
Deformation Dynamics ◽  
Recent Developments ◽  
New Research

“Smaller is stronger,” sub-, micro-, and nanomaterials exhibit high strength, ultralarge elasticity and unusual plastic and fracture behaviors which originate from their size effect and the low density of defects, different from their conventional bulk counterparts. To understand the structural evolution process under external stress at atomic scale is crucial for us to reveal the essence of these “unusual” phenomena and is momentous in the design of new materials. Our review presents the recent developments in the methods, techniques, instrumentation, and scientific progress of atomic scalein situdeformation dynamics on single crystalline nanowires. The super-large elasticity, plastic deformation mechanism transmission, and unusual fracture behavior related to the experimental mechanics of nanomaterials are reviewed.In situexperimental mechanics at the atomic scale open a new research field which is important not only to the microscopic methodology but also to the practice.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

The Use of Advanced Analytical Techniques for Characterization of the Chemical, Physical, and Crystallographic Nature of a Surface

1973 ◽  
Vol 31 ◽  
pp. 132-133 ◽  
Author(s):  
R. E. Herfert
Keyword(s):  
Surface Characterization ◽  
Analytical Techniques ◽  
X Ray Diffraction ◽  
Depth Of Penetration ◽  
X Ray ◽  
The Past ◽  
Transmission Electron ◽  
Scanning Electron

Studies of the nature of a surface, either metallic or nonmetallic, in the past, have been limited to the instrumentation available for these measurements. In the past, optical microscopy, replica transmission electron microscopy, electron or X-ray diffraction and optical or X-ray spectroscopy have provided the means of surface characterization. Actually, some of these techniques are not purely surface; the depth of penetration may be a few thousands of an inch. Within the last five years, instrumentation has been made available which now makes it practical for use to study the outer few 100A of layers and characterize it completely from a chemical, physical, and crystallographic standpoint. The scanning electron microscope (SEM) provides a means of viewing the surface of a material in situ to magnifications as high as 250,000X.

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