A Novel Test Design for Large Strain Uniaxial Reverse Loading of AZ31B Sheet Out of the Rolling Plane

2021 ◽  
Vol 143 (4) ◽  
Author(s):  
Amir Yazdanmehr ◽  
Ali A. Roostaei ◽  
Hamid Jahed
Keyword(s):  
Room Temperature ◽  
Large Strain ◽  
Rolling Plane ◽  
Plane Curves ◽  
Test Design ◽  
Thick Sheet ◽  
Data Generation ◽  
Element Simulation ◽  
Reverse Loading ◽  
Miniature Specimens

Abstract Understanding a magnesium alloy sheet's response to load reversals is important to accurately simulate and optimize a component's manufacturing process. Through this research, the room temperature compression-tension and tension-compression experiments with strains up to ∼12% are performed on AZ31B-H24 sheet specimens along the normal direction of a 6.35 mm-thick sheet. Miniature specimens machined through thickness are tested using a novel setup designed for large strain reverse loading data generation where specimen size is limited. The reliability of the devised setup is verified by finite element simulation and by reproducing in-plane curves obtained via an anti-buckling fixture. A shot peening process involving prevailing through-thickness deformation is modeled and numerical results indicate that employing only in-plane properties of magnesium sheets for simulating such processes can lead to inaccurate predictions.

scholarly journals The frontiers of functionalized graphene-based nanocomposites as chemical sensors

2021 ◽  
Vol 10 (1) ◽  
pp. 330-369
Author(s):  
Norizan M. Nurazzi ◽  
Norli Abdullah ◽  
Siti Z. N. Demon ◽  
Norhana A. Halim ◽  
Ahmad F. M. Azmi ◽  
...  
Keyword(s):  
Electron Mobility ◽  
Room Temperature ◽  
Chemical Sensor ◽  
Performance Enhancement ◽  
Ballistic Transport ◽  
Quantum Hall ◽  
Single Atom ◽  
Research Progress ◽  
Thick Sheet ◽  
High Electron

Abstract Graphene is a single-atom-thick sheet of sp2 hybridized carbon atoms that are packed in a hexagonal honeycomb crystalline structure. This promising structure has endowed graphene with advantages in electrical, thermal, and mechanical properties such as room-temperature quantum Hall effect, long-range ballistic transport with around 10 times higher electron mobility than in Si and thermal conductivity in the order of 5,000 W/mK, and high electron mobility at room temperature (250,000 cm2/V s). Another promising characteristic of graphene is large surface area (2,630 m2/g) which has emerged so far with its utilization as novel electronic devices especially for ultrasensitive chemical sensor and reinforcement for the structural component applications. The application of graphene is challenged by concerns of synthesis techniques, and the modifications involved to improve the usability of graphene have attracted extensive attention. Therefore, in this review, the research progress conducted in the previous decades with graphene and its derivatives for chemical detection and the novelty in performance enhancement of the chemical sensor towards the specific gases and their mechanism have been reviewed. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future improvements are also being included.

scholarly journals Experimental and Computational Approach to Fatigue Behavior of Polycrystalline Tantalum

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 416 ◽  
Author(s):  
Damien Colas ◽  
Eric Finot ◽  
Sylvain Flouriot ◽  
Samuel Forest ◽  
Matthieu Mazière ◽  
...  
Keyword(s):  
Free Surface ◽  
Low Cycle Fatigue ◽  
Large Strain ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Field Measurements ◽  
Test Sample ◽  
Lattice Rotation ◽  
Element Simulation ◽  
Crack Initiation Criterion

This work provides an experimental and computational analysis of low cycle fatigue of a tantalum polycrystalline aggregate. The experimental results include strain field and lattice rotation field measurements at the free surface of a tension–compression test sample after 100, 1000, 2000, and 3000 cycles at ±0.2% overall strain. They reveal the development of strong heterogeneites of strain, plastic slip activity, and surface roughness during cycling. Intergranular and transgranular cracks are observed after 5000 cycles. The Crystal Plasticity Finite Element simulation recording more than 1000 cycles confirms the large strain dispersion at the free surface and shows evidence of strong local ratcheting phenomena occurring in particular at some grain boundaries. The amount of ratcheting plastic strain at each cycle is used as the main ingredient of a new local fatigue crack initiation criterion.

Deformation and its Structure in Llo Ti-Al-Nb Compound Alloys

1988 ◽  
Vol 133 ◽  
Author(s):  
Yoo-Dong Hahn ◽  
Sung H. Whang
Keyword(s):  
Temperature Dependence ◽  
Yield Stress ◽  
Uniaxial Compression ◽  
High Temperatures ◽  
Room Temperature ◽  
Fracture Strain ◽  
Positive Temperature ◽  
Deformation Structures ◽  
Miniature Specimens ◽  
Deformation Tests

ABSTRACTThe ternary TiAl-Nb (Llo) alloys stabilized at 1000°C for a week were prepared into miniature specimens for compressive deformation tests. The specimens were deformed in uniaxial compression at room temperature as well as various high temperatures. The yield stress and fracture strain were determined with respect to Nb concentration, and as a function of temperature to investigate positive temperature dependence.Dislocation structures and other deformation structures of the deformed alloys were studied by TEM.

Extensive deformation behavior of an all-oxide Al2O3-TiO2 nanostructured multilayer ceramic at room temperature

2009 ◽  
Vol 24 (11) ◽  
pp. 3387-3396 ◽  
Author(s):  
Arcan F. Dericioglu ◽  
Y.F. Liu ◽  
Yutaka Kagawa
Keyword(s):  
Cross Sections ◽  
Deformation Behavior ◽  
Room Temperature ◽  
Temperature Deformation ◽  
Relative Movement ◽  
Element Simulation ◽  
Columnar Grains ◽  
Multilayer Ceramic ◽  
Extensive Deformation ◽  
Indentation Response

An all-oxide Al2O3-TiO2 ceramic multilayer composed of 10–100 nm thick alternating layers was fabricated using the reactive magnetron sputtering process. Microindentation tests were carried out on the multilayer ceramic followed by microstructural observations of the cross-sections of the indented sites to characterize the indentation response of the system. During the observations, it was noted that an extensive room temperature “deformation” occurred in the multilayer ceramic material. The material shows a thickness reduction of as much as ∼40% under a conical indenter at 300 mN of load without microcracking and dislocation-assisted deformation. The room temperature deformation mechanism is governed by the relative movement and rearrangement of the anisotropic nanoscale columnar grains along the intergranular boundaries containing elongated voids. The relative sliding along the intergranular boundaries, and the subsequent granular rotation under indentation were well captured by finite element simulation.

Cold-rolling of Ti-rich TiAl polysynthetically twinned crystals

1990 ◽  
Vol 5 (3) ◽  
pp. 484-487 ◽  
Author(s):  
S. R. Nishitani ◽  
M. H. Oh ◽  
A. Nakamura ◽  
T. Fujiwara ◽  
M. Yamaguchi
Keyword(s):  
Cold Rolling ◽  
Shear Deformation ◽  
Surface Texture ◽  
Room Temperature ◽  
Stoichiometric Composition ◽  
Rolling Direction ◽  
Rolling Plane ◽  
Total Reduction ◽  
Pole Figures

Polysynthetically twinned crystals of TiAl with a nearly stoichiometric composition have been grown and rolled at room temperature. The maximum total reduction in thickness which is attainable without fracture depends on lamellae orientation with respect to the rolling plane and rolling direction. When specimens are oriented such that shear deformation parallel to the lamellar planes is operative during rolling and its operation causes lengthening of specimens, such specimens can be rolled up to about 50% reduction in thickness. The (111) pole figures are determined for the surface of specimens rolled to several different amounts of reduction, and the formation of surface texture is briefly discussed.

Vibration Analysis of Linear Magnetostrictive Actuator

2011 ◽  
Vol 243-249 ◽  
pp. 6036-6039 ◽  
Author(s):  
Li Ping Qin ◽  
Yuan Jun Yan
Keyword(s):  
Vibration Analysis ◽  
Room Temperature ◽  
Large Strain ◽  
High Energy ◽  
High Energy Density ◽  
Initial State ◽  
Giant Magnetostrictive Materials ◽  
Magnetostrictive Actuator ◽  
Hysteretic Loss ◽  
Great Development

Giant magnetostrictive materials, such as Terfenol-D, have been used to make a principal driving element in actuator, owing to its fine characteristic that is large strain, high energy density, small hysteretic loss and less performance degradation in room temperature. With the discovery and refining of Terfenol-D, the magnetostrictive actuator has gotten great development for recent twenty years. The free vibration and forced vibratin of linear magnetostrictive actuator is analyzed. The initial state of rod is at rest. The computational results show that the displacement response is synchronous with the current.

Finite Element Simulation of Hillock Formation in Aluminum Interconnect

1991 ◽  
Vol 226 ◽  
Author(s):  
L. G. Burrell ◽  
S. Kapur ◽  
I. Shareef
Keyword(s):  
Finite Element ◽  
Large Strain ◽  
Permanent Deformation ◽  
Element Model ◽  
Linear Finite Element ◽  
Element Simulation ◽  
Creep Analysis ◽  
Hillock Formation ◽  
Plastic Creep ◽  
Abaqus Software

AbstractA non-linear finite element model has been used to simulate hillock formation in an aluminum interconnect structure. The hillock formation is caused by the thermal expansion mismatch between aluminum and the surrounding SiO2 passivation. Using the ABAQUS software [1], a large strain elastic-plastic-creep analysis was done. The results showed there were stresses large enough to cause yield and permanent deformation of the aluminum interconnect.

Residual Stress Measurements of 4H-SiC Crystals Using X-Ray Diffraction

2014 ◽  
Vol 778-780 ◽  
pp. 453-456 ◽  
Author(s):  
Masashi Nakabayashi ◽  
Tatsuo Fujimoto ◽  
Hiroshi Tsuge ◽  
Kiyoshi Kojima ◽  
Kozo Abe ◽  
...  
Keyword(s):  
Residual Stress ◽  
Temperature Distribution ◽  
Room Temperature ◽  
Radial Direction ◽  
Large Strain ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plane Direction ◽  
Lateral Temperature

The room temperature residual stress of 4H-SiC wafers has been investigated using a precise X-ray diffraction method. A large strain was observed for the circumferential direction of wafers, more than ten times larger than those measured along the principal plane direction and the radial direction. Optimizing the lateral temperature distribution in growing crystals leads to reduction of residual stress of wafers with high crystal quality.

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