scholarly journals Effects of Microsphere Size on the Mechanical Properties of Photonic Crystals

Crystals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 453 ◽  
Author(s):  
Yuemin Wang ◽  
Shuliang Dou ◽  
Lei Shang ◽  
Panpan Zhang ◽  
Xiangqiao Yan ◽  
...  
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Elastic Modulus ◽  
Photonic Crystals ◽  
High Performance ◽  
Deformation Model ◽  
Face Centered Cubic ◽  
Submicron Scale ◽  
Microsphere Size ◽  
Face Centered

Photonic crystal (PC) thin films that are self-assembled from different-sized silica microspheres were prepared for studying mechanical properties via nanoindentation at the submicron scale. We found that the silica photonic crystals (PCs) possessed a face-centered cubic (FCC) microstructure and their elastic modulus and hardness were in the range of ~1.81–4.92 GPa and 0.008–0.033 GPa, respectively. The calculated results proved that there were size-dependent properties in the silica PCs, in that the elastic modulus and hardness increased as the diameter decreased from 538 nm to 326 nm. After studying the total work and plastic work in the progressive deformation of silica PCs during the nanoindentation tests, we developed a two-stage deformation model to explain how the microsphere size affects the mechanical properties of PC thin films. The phenomenon of “smaller is stronger” is mainly due to the energy consumption, which combines the effects of microstructure collapse, microsphere slide, and reduced porosity during the whole loading and unloading process. In addition, the results of numerical simulation matched the experimental data and reflected the energy change rules of PCs during the indentation process. Furthermore, the study affords useful guidance for constructing high-performance films with proper design and potential application in next-generation PC materials.

Si Doped and Un-Doped CrN Thin Films Produced by Magnetron Sputtering: Structural and Mechanical Properties

2012 ◽  
Vol 18-19 ◽  
pp. 201-211 ◽  
Author(s):  
L. Cunha ◽  
C. Moura
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Crystallite Size ◽  
Processing Parameters ◽  
Preferred Orientation ◽  
Chromium Nitride ◽  
Face Centered Cubic ◽  
Face Centered ◽  
Silicon Doped

Chromium nitride and silicon doped chromium nitride thin films have been deposited by r.f. reactive magnetron sputtering. The effect of processing parameters on the properties of chromium nitride films and the correspondent influence of the addition of silicon on the chromium nitride matrix in the films structure and mechanical properties have been investigated. The characterization of the coatings was performed by X-ray diffraction (XRD), and nano-indentation experiments. These studies allow analyzing the crystalline phases, crystal orientation/texture, crystallite size, mechanical properties and the relations between the characteristics of the films. The increase of the nitrogen partial pressure in the working atmosphere produces changes from a body-centered cubic (bcc) Cr structure, to hexagonal Cr2N to face-centered cubic (fcc) CrN structure, with CrN (111) preferred orientation. For the films with a dominant Cr2N phase the hardness has a relative maximum (42 GPa). The highest hardness was measured for a coating with dominant CrN phase (45 GPa) with a crystallite size around 18 nm. The addition of Si, in the films with CrN dominant phase, maintains the CrN (111) preferred orientation and produced variable changes in films hardness, depending on deposition conditions.

scholarly journals Novel Co-Cu-Based Immiscible Medium-Entropy Alloys with Promising Mechanical Properties

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 238
Author(s):  
Sujung Son ◽  
Jongun Moon ◽  
Hyeonseok Kwon ◽  
Peyman Asghari Rad ◽  
Hidemi Kato ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Binary System ◽  
Design Methodology ◽  
Miscibility Gap ◽  
Face Centered Cubic ◽  
Solid Solution Strengthening ◽  
Solution Strengthening ◽  
Face Centered ◽  
Strength And Ductility ◽  
Cobalt Copper

New AlxCo50−xCu50−xMnx (x = 2.5, 10, and 15 atomic %, at%) immiscible medium-entropy alloys (IMMEAs) were designed based on the cobalt-copper binary system. Aluminum, a strong B2 phase former, was added to enhance yield strength and ultimate tensile strength, while manganese was added for additional solid solution strengthening. In this work, the microstructural evolution and mechanical properties of the designed Al-Co-Cu-Mn system are examined. The alloys exhibit phase separation into dual face-centered cubic (FCC) phases due to the miscibility gap of the cobalt-copper binary system with the formation of CoAl-rich B2 phases. The hard B2 phases significantly contribute to the strength of the alloys, whereas the dual FCC phases contribute to elongation mitigating brittle fracture. Consequently, analysis of the Al-Co-Cu-Mn B2-strengthened IMMEAs suggest that the new alloy design methodology results in a good combination of strength and ductility.

scholarly journals Effect of Sm Doping on the Microstructure, Mechanical Properties and Shape Memory Effect of Cu-13.0Al-4.0Ni Alloy

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4007
Author(s):  
Qimeng Zhang ◽  
Bo Cui ◽  
Bin Sun ◽  
Xin Zhang ◽  
Zhizhong Dong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Strengthening Effect ◽  
Face Centered Cubic ◽  
Compressive Fracture ◽  
Fine Grain ◽  
Fine Grain Strengthening ◽  
Face Centered

The effects of rare earth element Sm on the microstructure, mechanical properties, and shape memory effect of the high temperature shape memory alloy, Cu-13.0Al-4.0Ni-xSm (x = 0, 0.2 and 0.5) (wt.%), are studied in this work. The results show that the Sm addition reduces the grain size of the Cu-13.0Al-4.0Ni alloy from millimeters to hundreds of microns. The microstructure of the Cu-13.0Al-4.0Ni-xSm alloys are composed of 18R and a face-centered cubic Sm-rich phase at room temperature. In addition, because the addition of the Sm element enhances the fine-grain strengthening effect, the mechanical properties and the shape memory effect of the Cu-13.0Al-4.0Ni alloy were greatly improved. When x = 0.5, the compressive fracture stress and the compressive fracture strain increased from 580 MPa, 10.5% to 1021 MPa, 14.8%, respectively. When the pre-strain is 10%, a reversible strain of 6.3% can be obtained for the Cu-13.0Al-4.0Ni-0.2Sm alloy.

scholarly journals Development of Novel Lightweight Al-Rich Quinary Medium-Entropy Alloys with High Strength and Ductility

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4223
Author(s):  
Po-Sung Chen ◽  
Yu-Chin Liao ◽  
Yen-Ting Lin ◽  
Pei-Hua Tsai ◽  
Jason S. C. Jang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Compressive Strain ◽  
High Strength ◽  
Fine Tuning ◽  
Face Centered Cubic ◽  
Transportation Industry ◽  
High Entropy ◽  
Good Potential ◽  
Face Centered

Most high-entropy alloys and medium-entropy alloys (MEAs) possess outstanding mechanical properties. In this study, a series of lightweight nonequiatomic Al50–Ti–Cr–Mn–V MEAs with a dual phase were produced through arc melting and drop casting. These cast alloys were composed of body-centered cubic and face-centered cubic phases. The density of all investigated MEAs was less than 5 g/cm3 in order to meet energy and transportation industry requirements. The effect of each element on the microstructure evolution and mechanical properties of these MEAs was investigated. All the MEAs demonstrated outstanding compressive strength, with no fractures observed after a compressive strain of 20%. Following the fine-tuning of the alloy composition, the Al50Ti20Cr10Mn15V5 MEA exhibited the most compressive strength (~1800 MPa) and ductility (~34%). A significant improvement in the mechanical compressive properties was achieved (strength of ~2000 MPa, strain of ~40%) after annealing (at 1000 °C for 0.5 h) and oil-quenching. With its extremely high specific compressive strength (452 MPa·g/cm3) and ductility, the lightweight Al50Ti20Cr10Mn15V5 MEA demonstrates good potential for energy or transportation applications in the future.

scholarly journals Effects of Different Contents of Each Component on the Structural Stability and Mechanical Properties of Co-Cr-Fe-Ni High-Entropy Alloys

2021 ◽  
Vol 11 (6) ◽  
pp. 2832
Author(s):  
Haibo Liu ◽  
Cunlin Xin ◽  
Lei Liu ◽  
Chunqiang Zhuang
Keyword(s):  
Mechanical Properties ◽  
Structural Stability ◽  
High Entropy Alloys ◽  
Face Centered Cubic ◽  
Obvious Effect ◽  
High Entropy ◽  
Precise Control ◽  
Component Content ◽  
Face Centered ◽  
And Performance

The structural stability of high-entropy alloys (HEAs) is closely related to their mechanical properties. The precise control of the component content is a key step toward understanding their structural stability and further determining their mechanical properties. In this study, first-principle calculations were performed to investigate the effects of different contents of each component on the structural stability and mechanical properties of Co-Cr-Fe-Ni HEAs based on the supercell model. Co-Cr-Fe-Ni HEAs were constructed based on a single face-centered cubic (FCC) solid solution. Elemental components have a clear effect on their structure and performance; the Cr and Fe elements have an obvious effect on the structural stability and equilibrium lattice constant, respectively. The Ni elements have an obvious effect on stiffness. The Pugh ratios indicate that Cr and Ni addition may increase ductility, whereas Co and Fe addition may decrease it. With increasing Co and Fe contents or decreasing Cr and Ni contents, the structural stability and stiffness of Co-Cr-Fe-Ni HEAs are improved. The structural stability and mechanical properties may be related to the strength of the metallic bonding and covalent bonding inside Co-Cr-Fe-Ni HEAs, which, in turn, is determined by the change in element content. Our results provide the underlying insights needed to guide the optimization of Co-Cr-Fe-Ni HEAs with excellent mechanical properties.

scholarly journals Effects of Perpendicular Magnetic Field Annealing on the Structural and Magnetic Properties of [Co/Ni]2/PtMn Thin Films

2021 ◽  
Vol 7 (3) ◽  
pp. 38
Author(s):  
Roshni Yadav ◽  
Chun-Hsien Wu ◽  
I-Fen Huang ◽  
Xu Li ◽  
Te-Ho Wu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Films ◽  
Magnetic Properties ◽  
Photoelectron Spectroscopy ◽  
Perpendicular Magnetic Field ◽  
Face Centered Cubic ◽  
Lattice Image ◽  
X Ray ◽  
Field Annealing ◽  
Face Centered

In this study, [Co/Ni]2/PtMn thin films with different PtMn thicknesses (2.7 to 32.4 nm) were prepared on Si/SiO2 substrates. The post-deposition perpendicular magnetic field annealing (MFA) processes were carried out to modify the structures and magnetic properties. The MFA process also induced strong interlayer diffusion, rendering a less sharp interface between Co and Ni and PtMn layers. The transmission electron microscopy (TEM) lattice image analysis has shown that the films consisted of face-centered tetragonal (fct) PtMn (ordered by MFA), body-centered cubic (bcc) NiMn (due to intermixing), in addition to face-centered cubic (fcc) Co, Ni, and PtMn phases. The peak shift (2-theta from 39.9° to 40.3°) in X-ray diffraction spectra also confirmed the structural transition from fcc PtMn to fct PtMn after MFA, in agreement with those obtained by lattice images in TEM. The interdiffusion induced by MFA was also evidenced by the depth profile of X-ray photoelectron spectroscopy (XPS). Further, the magnetic properties measured by vibrating sample magnetometry (VSM) have shown an increased coercivity in MFA-treated samples. This is attributed to the presence of ordered fct PtMn, and NiMn phases exchange coupled to the ferromagnetic [Co/Ni]2 layers. The vertical shift (Mshift = −0.03 memu) of the hysteresis loops is ascribed to the pinned spins resulting from perpendicular MFA processes.

Synthesis and Fabrication of PVA-Ag-Cu and PANI-Ag-Cu Nanocomposite Thin Film Sensor for Detection of E. coli in Water

2014 ◽  
Vol 911 ◽  
pp. 131-135 ◽  
Author(s):  
H. Abdullah ◽  
Noor Azwen Noor Azmy ◽  
Norshafadzila Mohammad Naim ◽  
Aisyah Bolhan ◽  
Aidil Abdul Hamid ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Reduction ◽  
Oxidative Polymerization ◽  
Face Centered Cubic ◽  
High Concentration ◽  
Film Sensor ◽  
E Coli ◽  
Host Materials ◽  
Face Centered ◽  
Xrd Patterns

Polymers are excellent host materials for nanoparticles of metals and semiconductors. PVAAgCu nanocomposite was synthesized from chemical reduction, whereas PANIAgCu nanocomposite was synthesized by chemical oxidative polymerization. PVAAgCu and PANIAgCu thin films were deposited on the glass substrate by spin coating technique. The films were characterized by using XRD and AFM. The sensitivity of the samples was analyzed by IV measurement. The peaks in XRD patterns confirm the presence of Ag-Cu nanoparticles in face centered cubic structure. AFM images show the roughness of PVAAgCu and PANIAgCu increased as Ag concentration decreased and Cu concentration increased. I-V measurements indicate that the change in the current of the films increases with the presence of E. coli. The sensitivity on E. coli increases for PVAAgCu and PANIAgCu thin films with high concentration of Cu.

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