Ultrasoft silicon nanomembranes: thickness-dependent effective elastic modulus

Nanoscale ◽  
2019 ◽  
Vol 11 (32) ◽  
pp. 15184-15194 ◽  
Author(s):  
Ajit K. Katiyar ◽  
Ashwini Ann Davidson ◽  
Houk Jang ◽  
Yun Hwangbo ◽  
Byeori Han ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Effective Elastic Modulus ◽  
Low Modulus ◽  
Silicon Nanomembranes

The mechanical properties of ultrathin Si nanomembranes having thicknesses of 2 to 35 nm have been investigated by determining biaxial Young's modulus. The nanomembrane sample with thickness of 2 nm showed very low modulus value of 3.25 GPa.

Mechanical Properties of Ti-Cr-Sn-Zr Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 635-640 ◽  
Author(s):  
Yonosuke Murayama ◽  
Shuichi Sasaki ◽  
Hisamichi Kimura ◽  
Akihiko Chiba
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Biomedical Application ◽  
Young's Modulus ◽  
Mechanical Twinning ◽  
Β Phase ◽  
Low Modulus ◽  
Deformation Modes ◽  
Zr Alloy ◽  
Zr Alloys

Low modulus β Ti alloys are attractive for biomedical application. This work examines the mechanical properties of Ti-Cr-Sn-Zr system alloys, especially the effect of the varying alloy composition on the microstructure, the Young’s modulus and the deformation mechanism.The Young’s modulus of the alloy varies with the composition, which variation is caused mainly from the competition between the meta-stable β phase and ω phase.The deformation modes of the Ti-Cr-Sn-Zr alloy, which are the mechanical twinning, the deformation by slip and the deformation-induced transformation, also change depending on the composition of the alloy. The minimum of the Young’s modulusof the Ti-Cr-Sn-Zr alloy in this experiment was shown in the composition where the microstructure of the alloy changes from the martensitic structure to the meta-stable β structure.

Elastic Percolation in Nanocomposites with Impenetrable Ellipsoidal Inclusion (Comprehensive Study of Geometry and Interphase Thickness)

2016 ◽  
Vol 08 (04) ◽  
pp. 1650055
Author(s):  
Ziba Gharehnazifam ◽  
Majid Baniassadi ◽  
Karen Abrinia ◽  
Morad Karimpour ◽  
Mostafa Baghani
Keyword(s):  
Monte Carlo ◽  
Elastic Modulus ◽  
Monte Carlo Method ◽  
Young’S Modulus ◽  
Polymer Nanocomposites ◽  
Young's Modulus ◽  
Effective Elastic Modulus ◽  
The Monte Carlo Method ◽  
Inclusion Distribution ◽  
Comprehensive Study

In this paper, effects of percolation, shape, and interphase thickness of inclusions have been studied on the effective elastic modulus of polymer nanocomposites. Inclusion distribution within the RVE has been prescribed using the Monte Carlo method, and existence of a relationship between percolation and effective Young’s modulus has been investigated. Further studies were carried out to determine the effect of increased spherical, oblate, and prolate particles in conjunction with different interphase thicknesses. Results suggest that the elastic modulus increases with the interphase thickness, and the maximum strength is associated with prolate inclusions. It has been concluded that percolation has a significant effect on the strength of polymer nanocomposites, and that it results in a spike in the value of Young’s modulus.

scholarly journals Effect of Alloying Elements on the Mechanical Properties of Mo3Si

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 129
Author(s):  
Wei Bi ◽  
Shunping Sun ◽  
Shaoyi Bei ◽  
Yong Jiang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Alloying Elements ◽  
Covalent Bonds ◽  
Excellent Thermal Stability ◽  
Nb Doping ◽  
Effect Of Alloying

Molybdenum silicides are attractive high-temperature structural materials because of their excellent thermal stability and outstanding oxidation resistance at high temperatures. First-principles calculations were employed to investigate the effect of alloying elements (Cr, Nb, V, W, Al, Ga, and Ge) on the mechanical properties of Mo3Si. The structural stabilities of doped Mo3Si were calculated, showing that the Pm-3n structure was stable at the investigated low-doping concentration. The calculated elastic constants have also evaluated some essential mechanical properties of doped Mo3Si. Cr- and V-doping decreased the elastic modulus, while Al- and Nb-doping slightly increased the shear and Young’s modulus of Mo3Si. Furthermore, V-, Al- and Nb-doping decreased the B/G and Poisson ratio, suggesting that these elements could form strong covalent bonds, and decrease shear deformation and alloy ductility. Based on the three-dimensional contours and two-dimensional projection of the elastic modulus, Cr- and V-doping exhibited a significant influence on the anisotropy of the shear and Young’s modulus. According to charge density and density of states, the electronic structures of alloyed Mo3Si were further analyzed to reveal the doping effects.

Investigating the Effect of Stone-Wales Defect on Young Modulus of Armchair Single Wall Carbon Nanotube Using Molecular Dynamics Simulation

2010 ◽  
Author(s):  
H. Rezaei Nejad ◽  
M. Ghasemi ◽  
A. Shahabi ◽  
S. M. Mirnouri Langroudi
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Young Modulus ◽  
Effective Elastic Modulus ◽  
Md Simulations ◽  
Dynamics Simulation ◽  
Fortran Code ◽  
Wales Defect

Effect of Stone-Wales percentage defect on effective elastic modulus of single-walled carbon nanotubes (SWCNT) is investigated. The Stone-Wales defect is a crystallographic defect that happens in nanotubes and is believed to affect the nanotubes mechanical properties. In order to calculate the mechanical properties of SWCNTs under axial tension, molecular dynamics (MD) simulations using the Morse potential is performed. An in house FORTRAN code is developed and utilized. The Young’s modulus of the perfect SWCNTs and those with different defect percentage is obtained using the classical elasticity theory. It is observed that for low percentage of defect (less than 8%) as the diameter increases the Young’s modulus of SWCNTs slightly increases. However, for high percentage of defect (more than 8%) as diameter increases the Young modulus clearly decreases.

Measurement of Elastic Modulus and Residual Stress of Diamond Thin Films

2007 ◽  
Vol 329 ◽  
pp. 545-550 ◽  
Author(s):  
Dao Hui Xiang ◽  
Ming Chen ◽  
Y.P. Ma ◽  
Fang Hong Sun
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Residual Stress ◽  
Elastic Modulus ◽  
Young’S Modulus ◽  
Diamond Film ◽  
Young's Modulus ◽  
Effective Means ◽  
Bulge Test ◽  
Diamond Thin Films

Despite great advancements in diamond thin film growth and deposition techniques, determination of the residual stress and Young’s modulus for diamond films has continued to be a challenge. The bulge test is a potentially powerful tool for characterizing the mechanical properties of diamond film. In a bulge tester, pressure is applied on a thin membrane and the out-of-plane deflection of the membrane center is measured. The Young’s Modulus and the residual stress are simultaneously determined by using the load-deflection behavior of a membrane. By means of electron-enhanced hot filament chemical vapor deposition (HFCVD), a diamond film was deposited on silicon slice (100), and the free-standing window sample of diamond thin films was fabricated by means of photolithography and anisotropic wet etching. The deflection of the membranes is measured using a laser interferometry system. The elastic modulus and residual stress were measured using a self-designed bulge equipment. In addition, the distortion of diamond thin films under different pressure was simulated using finite element analysis and the contrast was made with experimental data. The research indicated that the Young’s Modulus of diamond thin films is 937.8GPa and the residual stress is -10.53MPa. The elastic modulus and the residual stress coincide with the report in the literature and the value tested by X-ray diffraction, respectively. This method uses a simple apparatus, and the fabrication of samples is very easy, and it has provided an effective means for precise measure the mechanical properties of other thin films.

scholarly journals Investigation of the Local Mechanical Properties of the SAC Solder Joint with AFM

2017 ◽  
Vol 885 ◽  
pp. 269-274
Author(s):  
Judit Kámán ◽  
Attila Bonyár
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Solder Joint ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Contact Mode ◽  
Tapping Mode ◽  
Different Characteristics ◽  
Spring Constants ◽  
Sac Solder

Considering the size of the natural appearance of the micro alloy components of a SAC solder joint, AFM was used to investigate their mechanical properties in the form of their natural appearance. Contact-mode point-spectroscopy was done to determine the elastic modulus and tapping-mode point-spectroscopy was done to investigate the tip-sample power dissipation.The measured Young’s modulus values of the Cu, IML, Ag3Sn and Sn components, were 125±9 GPa, 111±20 GPa, 67±11 GPa and 57±16 GPa, respectively. The dissipation measurements were accomplished by Si and diamond probes with different spring constants. The different characteristics of the results are discussed.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

scholarly journals Experimental and Numerical Analysis of the Mechanical Properties of a Pretreated Shape Memory Alloy Wire in a Self-Centering Steel Brace

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 80
Author(s):  
Bo Zhang ◽  
Sizhi Zeng ◽  
Fenghua Tang ◽  
Shujun Hu ◽  
Qiang Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Energy Dissipation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Loading Rate ◽  
Effective Elastic Modulus ◽  
Maximum Energy ◽  
Numerical Results ◽  
Energy Dissipation Capacity

As a stimulus-sensitive material, the difference in composition, fabrication process, and influencing factors will have a great effect on the mechanical properties of a superelastic Ni-Ti shape memory alloy (SMA) wire, so the seismic performance of the self-centering steel brace with SMA wires may not be accurately obtained. In this paper, the cyclic tensile tests of a kind of SMA wire with a 1 mm diameter and special element composition were tested under multi-working conditions, which were pretreated by first tensioning to the 0.06 strain amplitude for 40 cycles, so the mechanical properties of the pretreated SMA wires can be simulated in detail. The accuracy of the numerical results with the improved model of Graesser’s theory was verified by a comparison to the experimental results. The experimental results show that the number of cycles has no significant effect on the mechanical properties of SMA wires after a certain number of cyclic tensile training. With the loading rate increasing, the pinch effect of the hysteresis curves will be enlarged, while the effective elastic modulus and slope of the transformation stresses in the process of loading and unloading are also increased, and the maximum energy dissipation capacity of the SMA wires appears at a loading rate of 0.675 mm/s. Moreover, with the initial strain increasing, the slope of the transformation stresses in the process of loading is increased, while the effective elastic modulus and slope of the transformation stresses in the process of unloading are decreased, and the maximum energy dissipation capacity appears at the initial strain of 0.0075. In addition, a good agreement between the test and numerical results is obtained by comparing with the hysteresis curves and energy dissipation values, so the numerical model is useful to predict the stress–strain relations at different stages. The test and numerical results will also provide a basis for the design of corresponding self-centering steel dampers.

scholarly journals First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Group Vi ◽  
Group V ◽  
Β Phase ◽  
Ti Alloys ◽  
Ω Phase ◽  
Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

scholarly journals Tailoring a Low Young Modulus for a Beta Titanium Alloy by Combining Severe Plastic Deformation with Solution Treatment

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3467
Author(s):  
Anna Nocivin ◽  
Doina Raducanu ◽  
Bogdan Vasile ◽  
Corneliu Trisca-Rusu ◽  
Elisabeta Mirela Cojocaru ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Solution Treatment ◽  
Young Modulus ◽  
Orthopedic Implants ◽  
Beta Titanium Alloy

The present paper analyzed the microstructural characteristics and the mechanical properties of a Ti–Nb–Zr–Fe–O alloy of β-Ti type obtained by combining severe plastic deformation (SPD), for which the total reduction was of etot = 90%, with two variants of super-transus solution treatment (ST). The objective was to obtain a low Young’s modulus with sufficient high strength in purpose to use the alloy as a biomaterial for orthopedic implants. The microstructure analysis was conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM) investigations. The analyzed mechanical properties reveal promising values for yield strength (YS) and ultimate tensile strength (UTS) of about 770 and 1100 MPa, respectively, with a low value of Young’s modulus of about 48–49 GPa. The conclusion is that satisfactory mechanical properties for this type of alloy can be obtained if considering a proper combination of SPD + ST parameters and a suitable content of β-stabilizing alloying elements, especially the Zr/Nb ratio.

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