Probing the size- and constituent-mediated mechanical properties and deformation behavior in crystalline/amorphous nanolaminates

Nanoscale ◽  
2018 ◽  
Vol 10 (46) ◽  
pp. 21827-21841 ◽  
Author(s):  
Y. Q. Wang ◽  
K. Wu ◽  
J. Y. Zhang ◽  
G. Liu ◽  
J. Sun
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Shear Transformation ◽  
Shear Transformation Zones ◽  
Tunable Mechanical Properties

The tunable mechanical properties and deformation behavior in crystalline/amorphous nanolaminates are revealed to be through cooperation between dislocations and shear transformation zones.

scholarly journals Influence of grain size and composition, topology and excess free volume on the deformation behavior of Cu–Zr nanoglasses

2015 ◽  
Vol 6 ◽  
pp. 537-545 ◽  
Author(s):  
Daniel Şopu ◽  
Karsten Albe
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Free Volume ◽  
Deformation Behavior ◽  
Alloy Composition ◽  
Topological Order ◽  
Shear Transformation ◽  
Shear Transformation Zones ◽  
Dynamics Simulations ◽  
Topological Disorder

The influence of grain size and composition on the mechanical properties of Cu–Zr nanoglasses (NGs) is investigated by molecular dynamics simulations using two model glasses of different alloy composition, namely Cu64Zr36 (Cu-rich) and Cu36Zr64 (Zr-rich). When the grain size is increased, or the fraction of interfaces in these NGs is decreased, we find a transition from a homogeneous to an inhomogeneous plastic deformation, because the softer interfaces are promoting the formation shear transformation zones. In case of the Cu-rich system, shear localization at the interfaces is most pronounced, since both the topological order and free volume content of the interfaces are very different from the bulk phase. After thermal treatment the redistribution of free volume leads to a more homogenous deformation behavior. The deformation behavior of the softer Zr-rich nanoglass, in contrast, is only weakly affected by the presence of glass–glass interfaces, since the interfaces don’t show topological disorder. Our results provide clear evidence that the mechanical properties of metallic NGs can be systematically tuned by controlling the size and the chemical composition of the glassy nanograins.

scholarly journals Effect of Hydrogen Charging on Pop-in Behavior of a Zr-Based Metallic Glass

Metals ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 22 ◽  
Author(s):  
Lin Tian ◽  
Dominik Tönnies ◽  
Moritz Hirsbrunner ◽  
Tim Sievert ◽  
Zhiwei Shan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Spatial Correlation ◽  
Hydrogen Content ◽  
Amorphous Structure ◽  
Homogeneous Deformation ◽  
Hydrogen Charging ◽  
Shear Transformation ◽  
Shear Transformation Zones ◽  
Clear Increase

In this work, structural and mechanical properties of hydrogen-charged metallic glass are studied to evaluate the effect of hydrogen on early plasticity. Hydrogen is introduced into samples of a Zr-based (Vit 105) metallic glass using electrochemical charging. Nanoindentation tests reveal a clear increase in modulus and hardness as well as in the load of the first pop-in with increasing hydrogen content. At the same time, the probability of a pop-in occurring decreases, indicating that hydrogen hinders the onset of plastic instabilities while allowing local homogeneous deformation. The hydrogen-induced stiffening and hardening is rationalized by hydrogen stabilization of shear transformation zones (STZs) in the amorphous structure, while the improved ductility is attributed to the change in the spatial correlation of the STZs.

scholarly journals Effect of Annealing on Strain Rate Sensitivity of Metallic Glass under Nanoindentation

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1063
Author(s):  
Mingcan Li
Keyword(s):  
Mechanical Properties ◽  
Metallic Glass ◽  
Strain Rate ◽  
Strain Rate Sensitivity ◽  
Annealing Time ◽  
Isothermal Annealing ◽  
Rate Sensitivity ◽  
Underlying Mechanism ◽  
Shear Transformation ◽  
Shear Transformation Zones

The influence of isothermal annealing on the strain rate sensitivity (SRS) of a Zr-based bulk metallic glass (BMG) was investigated by nanoindentation. A more positive SRS is observed with a decrease in the content of the free volume (FV) of the sample. Furthermore, the SRS becomes nearly constant with increasing annealing time when the FV is annealed out. By taking into consideration the FV-assisted activation and combination of the shear transformation zones (STZs), the underlying mechanism is well understood. The current work may offer useful insights into the correlation between the microstructure and mechanical properties of BMGs.

Severe plastic deformation of Al-1%Cu Alloy processed by a Simple Cyclic Extrusion Compression technique

2018 ◽  
Vol 1 (1) ◽  
pp. 77-90
Author(s):  
Walaa Abdelaziem ◽  
Atef Hamada ◽  
Mohsen A. Hassan
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Deformation Behavior ◽  
Cast Alloy ◽  
Surface Hardness ◽  
Grain Structure ◽  
Compression Technique ◽  
Cu Alloy ◽  
Cyclic Extrusion Compression

Severe plastic deformation is an effective method for improving the mechanical properties of metallic alloys through promoting the grain structure. In the present work, simple cyclic extrusion compression technique (SCEC) has been developed for producing a fine structure of cast Al-1 wt. % Cu alloy and consequently enhancing the mechanical properties of the studied alloy. It was found that the grain structure was significantly reduced from 1500 µm to 100 µm after two passes of cyclic extrusion. The ultimate tensile strength and elongation to failure of the as-cast alloy were 110 MPa and 12 %, respectively. However, the corresponding mechanical properties of the two pass CEC deformed alloy are 275 MPa and 35%, respectively. These findings ensure that a significant improvement in the grain structure has been achieved. Also, cyclic extrusion deformation increased the surface hardness of the alloy by 49 % after two passes. FE-simulation model was adopted to simulate the deformation behavior of the material during the cyclic extrusion process using DEFORMTM-3D Ver11.0. The FE-results revealed that SCEC technique was able to impose severe plastic strains with the number of passes. The model was able to predict the damage, punch load, back pressure, and deformation behavior.

scholarly journals 3D Printing of High Viscosity Reinforced Silicone Elastomers

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2239
Author(s):  
Nicholas Rodriguez ◽  
Samantha Ruelas ◽  
Jean-Baptiste Forien ◽  
Nikola Dudukovic ◽  
Josh DeOtte ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
New Technologies ◽  
Three Dimensional ◽  
High Viscosity ◽  
Layer By Layer ◽  
Silicone Elastomers ◽  
Uv Curable ◽  
Octet Truss ◽  
Tunable Mechanical Properties

Recent advances in additive manufacturing, specifically direct ink writing (DIW) and ink-jetting, have enabled the production of elastomeric silicone parts with deterministic control over the structure, shape, and mechanical properties. These new technologies offer rapid prototyping advantages and find applications in various fields, including biomedical devices, prosthetics, metamaterials, and soft robotics. Stereolithography (SLA) is a complementary approach with the ability to print with finer features and potentially higher throughput. However, all high-performance silicone elastomers are composites of polysiloxane networks reinforced with particulate filler, and consequently, silicone resins tend to have high viscosities (gel- or paste-like), which complicates or completely inhibits the layer-by-layer recoating process central to most SLA technologies. Herein, the design and build of a digital light projection SLA printer suitable for handling high-viscosity resins is demonstrated. Further, a series of UV-curable silicone resins with thiol-ene crosslinking and reinforced by a combination of fumed silica and MQ resins are also described. The resulting silicone elastomers are shown to have tunable mechanical properties, with 100–350% elongation and ultimate tensile strength from 1 to 2.5 MPa. Three-dimensional printed features of 0.4 mm were achieved, and complexity is demonstrated by octet-truss lattices that display negative stiffness.

Mechanical properties and deformation behavior of Ti–5Cr–xFe alloys

2009 ◽  
Vol 472 (1-2) ◽  
pp. 546-550 ◽  
Author(s):  
Wen-Fu Ho ◽  
Chang-Hung Pan ◽  
Shih-Ching Wu ◽  
Hsueh-Chuan Hsu
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior

Grain Refinement and Deformation Behavior of Ultrafine Grained Pd and Pd-Ag Alloys Produced by HPT

2008 ◽  
Vol 584-586 ◽  
pp. 182-187
Author(s):  
Lilia Kurmanaeva ◽  
Yulia Ivanisenko ◽  
J. Markmann ◽  
Ruslan Valiev ◽  
Hans Jorg Fecht
Keyword(s):  
Mechanical Properties ◽  
Deformation Behavior ◽  
Materials Science ◽  
High Pressure Torsion ◽  
Uniform Elongation ◽  
Grain Structure ◽  
Coarse Grained ◽  
Ultrafine Grain ◽  
Ultrafine Grained ◽  
Ultrafine Grain Structure

Investigations of mechanical properties of nanocrystalline (nc) materials are still in interest of materials science, because they offer wide application as structural materials thanks to their outstanding mechanical properties. NC materials demonstrate superior hardness and strength as compared with their coarse grained counterparts, but very often they possess a limited ductility or show low uniform elongation due to poor strain hardening ability. Here, we present the results of investigation of the microstructure and mechanical properties of nc Pd and Pd-x%Ag (x=20, 60) alloys. The initially coarse grained Pd-x% Ag samples were processed by high pressure torsion, which resulted in formation of homogenous ultrafine grain structure. The increase of Ag contents led to the decrease of the resulted grain size and change in deformation behavior, because of decreasing of stacking fault energy (SFE). The samples with larger Ag contents demonstrated the higher values of hardness, yield stress and ultimate stress. Remarkably the uniform elongation had also increased with increase of strength.

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