Size Effect in the Plasticity of Multiscale Nanofilamentary Cu/Nb Composite Wires During in-situ Tensile Tests Under Neutron Beam

2006 ◽  
Vol 977 ◽  
Author(s):  
Vanessa Vidal ◽  
Ludovic Thilly ◽  
Steven Van Petegem ◽  
Uwe Stuhr ◽  
Florence Lecouturier ◽  
...  
Keyword(s):  
Size Effect ◽  
Neutron Beam ◽  
Load Transfer ◽  
High Strength ◽  
Tensile Tests ◽  
Copper Matrix ◽  
Lattice Strains ◽  
Matrix Embedding ◽  
Pulsed Magnets

AbstractCopper-based high strength nanofilamentary wires reinforced by bcc nanofilaments (Nb or Ta) are prepared by severe plastic deformation for the winding of high pulsed magnets. In-situ tensile tests under neutron beam were performed on a Cu/Nb nanocomposite composed of a multiscale Cu matrix embedding 554 Nb filaments with a diameter of 267 nm and spacing of 45 nm. The evolution of elastic strains for individual lattice plane in each phase and peak profiles in the copper matrix versus applied stress evidenced the co-deformation behavior with different elastic-plastic regimes and load sharing: the Cu matrix exhibits size effect in the finest channels while the Nb nanowhiskers remain elastic up to the macroscopic failure, with a strong load transfer from the copper matrix onto zones that are still in the elastic regime. Taking into account results from residual lattice strains also determined by neutron diffraction, the yield stress in the finest Cu channels is in agreement with calculations based on a single dislocation regime.

scholarly journals S31 Size Effect in the Plasticity of Multiscale Nanofilamentary Cu/Nb Composite Wires During In-Situ Tensile Tests Under Neutron Beam

2008 ◽  
Vol 23 (2) ◽  
pp. 185-185
Author(s):  
V. Vidal ◽  
L. Thilly ◽  
P. O. Renault ◽  
U. Stuhr ◽  
S. Van Petegem ◽  
...  
Keyword(s):  
Size Effect ◽  
Neutron Beam ◽  
Tensile Tests ◽  
Composite Wires

Exploration of novel faying surface treatment for high-strength frictional bolted joints to enhance its after-slip performance

2021 ◽  
Author(s):  
Hitoshi Moriyama ◽  
Ryo Sakura ◽  
Takashi Yamaguchi ◽  
Takai Toshikazu ◽  
Yuta Yamamoto
Keyword(s):  
Surface Treatment ◽  
Load Transfer ◽  
High Strength ◽  
Bolted Joints ◽  
Deformation Capacity ◽  
Slip Coefficient ◽  
Faying Surface ◽  
Treatment Concepts ◽  
Local Slip

<p>Welded joints is adopted rather than bolted joints for megastructure’s connections because the former can carry large force. However, the former has several problems, such as quality control of welding in situ, which the latter can solve. By contrast, as the load transfer ratio of each bolt becomes uneven proportionally to the number of bolts, local slip around extreme bolts occurs before the whole slip. Extreme bolts to which a large shear force is applied will break before other bolts. For utilizing the strength of all bolts, the problem is solved by improving shear deformation capacity in faying surface with novel surface treatment. Here, the treatment concepts were explored, and the coating’s effectiveness was evaluated through friction tests. The deformation capacity can be twice or more than that of conventional treatment, and the slip coefficient doesn’t depend on contact pressure. These features have the advantage to give stable slip behaviour.</p>

Localization of Stresses in Polycrystalline Grains Measured by Neutron Diffraction and Predicted by Self-Consistent Model

2011 ◽  
Vol 681 ◽  
pp. 103-108
Author(s):  
Anita Gaj ◽  
Lea le Joncour ◽  
Andrzej Baczmanski ◽  
Sebastian Wroński ◽  
Benoit Panicaud ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Load Transfer ◽  
Diffraction Method ◽  
Lattice Strains ◽  
Consistent Model ◽  
Self Consistent ◽  
Main Component ◽  
Critical Resolved Shear Stress ◽  
Elastic Lattice

Time of flight neutron diffraction method was applied to measure elastic lattice strains in austenitic steel during "in situ" tensile test. Comparing experimental data with self-consistent model, the critical resolved shear stress and hardening parameters were determined for polycrystalline grains. The result allowed us to determine the main component of the stress localization tensor, relating the rate of grain stress with the applied macrostress rate. The evolution of concentration tensor in function of the applied macrostress was analyzed. Finally, the load transfer between grains during yielding of the sample was studied.

Development of High Strength Alloys in the Mg-Ni-Y-RE System

2007 ◽  
Vol 567-568 ◽  
pp. 385-388 ◽  
Author(s):  
P. Pérez ◽  
S. González ◽  
G. Garcés ◽  
G. Caruana ◽  
P. Adeva
Keyword(s):  
Magnesium Alloy ◽  
Load Transfer ◽  
Volume Fraction ◽  
Hot Extrusion ◽  
High Strength ◽  
High Volume ◽  
Magnesium Matrix ◽  
Fine Grained ◽  
Matrix Embedding ◽  
Second Phases

The microstructural and mechanical characterization of two alloys within the Mg-Ni-YRE system prepared by casting and subsequent hot extrusion at 400°C have been carried out. The microstructure of both materials consists of a fine-grained magnesium matrix embedding a high volume fraction of second phases; coarse Mg12RE and long period ordered stacking structure (LPS phase) and fine Mg2Ni particles. Both alloys show high strength values up to 250°C. The yield stress values at room temperature are 295 and 405 MPa for low- and high-alloyed magnesium alloy, respectively. Load transfer from the magnesium matrix to coarse Mg12RE and LPS particles account for the high strength of both alloys at temperatures below 250°C. Above this temperature both alloys exhibit a superplastic behaviour at low stresses with elongations of 700 and 450 % for the low and high-alloyed magnesium alloy, respectively.

Plasticity Mechanisms in Multi-Scale Copper-Based Nanocomposite Wires

2007 ◽  
Vol 539-543 ◽  
pp. 814-819 ◽  
Author(s):  
Ludovic Thilly ◽  
Vanessa Vidal ◽  
Florence Lecouturier
Keyword(s):  
Plastic Deformation ◽  
Size Effects ◽  
Hot Extrusion ◽  
High Strength ◽  
Cold Drawing ◽  
High Yield ◽  
Multi Scale ◽  
Pulsed Magnets ◽  
In Situ Deformation

Copper-based high strength nanofilamentary wires reinforced by Nb nanofilaments are prepared by severe plastic deformation (repeated hot extrusion, cold drawing and bundling steps) for the winding of high pulsed magnets. The effects of microstructure refinement on the plasticity mechanisms were studied via nanoindentation, in-situ deformation in TEM and under neutron beam: all results evidence size effects in each nanostructured phase of the nanocomposite wires, i.e. single dislocation regime in the finest regions of the Cu matrix and whisker-like behaviour in the Nb nanofilaments. The macroscopic high yield stress is thus the results of the combination of the different elastic-plastic regimes of each phase that include size effects.

Neutron Diffraction Analysis of Load Transfer in DP 600 Steel During In Situ Tensile Tests

2011 ◽  
Vol 681 ◽  
pp. 31-36
Author(s):  
Marc Seefeldt ◽  
Steven Dillien ◽  
Uwe Stuhr
Keyword(s):  
Neutron Diffraction ◽  
Inflection Point ◽  
Load Transfer ◽  
Volume Fraction ◽  
Tensile Tests ◽  
Martensite Phase ◽  
Lattice Plane ◽  
Hard Phase ◽  
Plastic Part

The load transfer among ferrite orientations and between ferrite and martensite was analysed in DP 600 steel by means of neutron diffraction duringin situtensile tests on the multiple pulse overlap time-of-flight strain scanner POLDI. The material had 0.07 wt% C and a martensite volume fraction of 15%.In situtests were done in “Young” as well as in “Poisson setup”. The martensite phase could not be probed due to its low tetragonality. The curves of the lattice plane strains as a function of the externally applied macroscopic stress reveal (1) plastic relaxations of transformation and intergranular stresses in the compliant <100> oriented grains, and (2) a second inflection point in the fully plastic part indicating the onset of plastic deformation of the hard phase.

TEM Investigations of Titanium Processed by ECAP Followed by Cold Rolling

2006 ◽  
Vol 503-504 ◽  
pp. 805-810 ◽  
Author(s):  
Bernhard Mingler ◽  
V.V. Stolyarov ◽  
Michael Zehetbauer ◽  
Wolfgang Lacom ◽  
Hans Peter Karnthaler
Keyword(s):  
Cold Rolling ◽  
Room Temperature ◽  
High Strength ◽  
Tensile Tests ◽  
Coarse Grained ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Cp Ti ◽  
Annealing Experiments

Conventional coarse grained (CG) commercial pure (CP) Ti Grade 2 was studied after cold rolling (CR) at room temperature, and after equal channel angular pressing (ECAP) at 450° C followed by CR, by transmission electron microscopy (TEM) methods. CR of the CG material leads to a microstructure showing initially twins with (0112) type and later subgrains separated by lowangle grain boundaries. CR carried out after ECAP yields the fragmentation of fine grains (300 – 800 nm) mostly bounded by high-angle boundaries into elongated subgrains (~ 100 nm). It was shown with in-situ annealing experiments in the TEM that this microstructure is thermally stable up to a temperature of 450° C. Tensile tests showed that the combination of ECAP with CR has the potential to produce at the same time high strength (941 MPa) and high ductility (16.7%).

scholarly journals Buildup of Multi-Ionic Supramolecular Network Facilitated by In-Situ Intercalated Organic Montmorillonite in 1,2-Polybutadiene

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 492 ◽  
Author(s):  
Jinhui Liu ◽  
Di Li ◽  
Xiangshuai Zhao ◽  
Jieting Geng ◽  
Jing Hua ◽  
...  
Keyword(s):  
High Strength ◽  
Crosslinking Density ◽  
Tensile Tests ◽  
Polymer Chains ◽  
Supramolecular Network ◽  
Tem Analysis ◽  
Organic Montmorillonite ◽  
Dielectric Performance ◽  
Novel Strategy

The development of a sacrificial bond provided unique inspiration for the design of advanced elastomers with excellent mechanical properties, but it is still a huge challenge to construct a homogenous polar sacrificial network in a nonpolar elastomer. In this effort, we proposed a novel strategy to engineer a multi-ionic network into a covalently cross-linked 1,2-polybutadiene (1,2-PB) facilitated by in-situ intercalated organic montmorillonite (OMMT) without phase separation. XRD, SEM, and TEM analysis were carried out to characterize the microstructure of the resulting polymers. Crosslinking density, dielectric performance, and cyclic tensile tests were used to demonstrate the interaction of zinc methacrylate (ZDMA) and OMMT. The dynamic nature of ionic bonds allowed it to rupture and reform to dissipate energy efficiently. Stretching orientation brought parallelism between polymer chains and OMMT layers which was beneficial for the reconstruction of the ionic network, ultimately resulting in high strength and a low stress relaxation rate. Overall, our work presented the design of a uniform and strong sacrificial network in the nano-clay/elastomer nanocomposite with outstanding mechanical performances under both static and dynamic conditions.

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