scholarly journals Enhanced strength of nano-polycrystalline diamond by introducing boron carbide interlayers at the grain boundaries

2020 ◽  
Vol 2 (2) ◽  
pp. 691-698 ◽  
Author(s):  
Bo Zhao ◽  
Shengya Zhang ◽  
Shuai Duan ◽  
Jingyan Song ◽  
Xiangjun Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Boron Carbide ◽  
Grain Boundaries ◽  
Materials Science ◽  
Polycrystalline Diamond ◽  
Excellent Thermal Stability

Polycrystalline diamond with high mechanical properties and excellent thermal stability plays an important role in industry and materials science.

Effect of Long-Term Aging on Microstructure and Mechanical Properties of a Wrought Ni-Base Superalloy

2015 ◽  
Vol 816 ◽  
pp. 546-550
Author(s):  
Chao Yuan ◽  
Huan Wang ◽  
Jian Ting Guo ◽  
He Yong Qin
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Room Temperature ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Increasing Trend ◽  
Size And Morphology ◽  
Strength And Plasticity ◽  
Base Superalloy

During long-term and high temperature service, microstructures of superalloys may change and then have an adverse impact on mechanical properties, so the stabilities of a wrought Ni-base superalloy aging without stress at 650°C were investigated in this paper. The results showed that the size and morphology of γ' precipitates in the alloy were not obviously influenced with the increase of exposure time, and primary MC carbides present excellent thermal stability. Moreover, almost no detrimental phase was found. Tensile strength and plasticity at room temperature after aging remained steady. Under the condition of 650°C/823MPa, the stress ruptures life presented increasing trend overall and plasticity decreases slightly. In conclusion, the experiment alloy presents a good thermal stability at 650°C.

Carbon nanotube reinforced polylactide/basalt fiber composites containing aluminium hypophosphite: thermal degradation, flame retardancy and mechanical properties

RSC Advances ◽  
2015 ◽  
Vol 5 (128) ◽  
pp. 105869-105879 ◽  
Author(s):  
Wei Yang ◽  
Zhongjing Jia ◽  
Yani Chen ◽  
Yunran Zhang ◽  
Jingyu Si ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Carbon Nanotube ◽  
Thermal Degradation ◽  
Flame Retardancy ◽  
Basalt Fiber ◽  
Fiber Composites ◽  
Melt Blending ◽  
Excellent Thermal Stability ◽  
Blending Method

Modified carbon nanotube reinforced polylactide/basalt fiber composites containing aluminium hypophosphite were prepared via melt blending method. The composites showed excellent thermal stability, flame retardancy, and mechanical properties.

Morphology, Structure and Properties of Electrospun Multi-Walled Carbon Nanotube/Polysulfonamide Composite Nanofibers

2015 ◽  
Vol 10 (1) ◽  
pp. 155892501501000 ◽  
Author(s):  
Bin-Jie Xin ◽  
Wenjie Chen
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Composite Nanofibers ◽  
Electrospun Fibers ◽  
Structure And Properties ◽  
Excellent Thermal Stability ◽  
Multi Walled Carbon Nanotube ◽  
Composite Nanofiber ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this paper, the morphology, structure and properties of electrospun Polysulfonamide (PSA)/multi-walled carbon nanotubes (MWCNTs) fibers are investigated systematically. The experimental results indicate that the diameter of electrospun PSA fiber increased by the blending of MWCNTs while its crystallinity decreased. Both the conductivity and mechanical properties of PSA/MWCNT fibers were improved by the blending of MWCNTs at a concentration below 5% MWCNT. The thermal behavior of the electrospun fibers was influenced by the MWCNT concentrations through the Thermogravimetric Analysis (TGA). The new developed PSA/MWCNTs composite nanofiber has excellent thermal stability and mechanical properties compared with the usual PSA fibers.

High-Performance Copolymerized Poly(m-Phenylene Isophthalamide) (PMIA) Fibers Containing Ether Moiety: Preparation, Structure and Properties

2019 ◽  
Vol 960 ◽  
pp. 140-147
Author(s):  
Na Li ◽  
Xing Ke Zhang ◽  
Jun Rong Yu ◽  
Yan Wang ◽  
Jing Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Performance ◽  
Molar Ratio ◽  
Wet Spinning ◽  
Structure And Properties ◽  
Dye Uptake ◽  
Excellent Thermal Stability ◽  
Polycondensation Process ◽  
Solution Polycondensation

Copolymerized poly (m-phenylene isophthalamide) (co-PMIA) fibers with excellent thermal stability and good mechanical properties were developed via solution polycondensation process based on m-phenylenediamine (MPD), isophthaloyl dichloride (IPC), and 3,4′-oxydianiline (3,4′-ODA). Effects of the ether moiety on the structure and properties of the copolymers were investigated. A series of co-PMIA nascent fibers were produced using wet-spinning method. The coagulation process to form co-PMIA nascent fibers were studied by examination of SEM and strength tester. The co-PMIA nascent fibers with the MPD/3,4′-ODA molar ratio of 8:2 showed an optimum dye uptake. Keywords: Copolymerization; High performance material; Wet spinning; Dyeability.

scholarly journals Thermal Stability and Recrystallization of Titanium Grade 4 with Ultrafine-Grained Structure

2020 ◽  
Vol 321 ◽  
pp. 11060
Author(s):  
Grigory Dyakonov ◽  
Sergey Mironov ◽  
Tatyana Yakovleva ◽  
Irina Semenova
Keyword(s):  
Thermal Stability ◽  
Grain Boundaries ◽  
Excellent Thermal Stability ◽  
Annealing Behavior ◽  
Ultrafine Grained Structure ◽  
Enhanced Diffusion ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Mean Grain Size ◽  
Titanium Grade

The paper examined annealing behavior of ultrafine-grained Ti Grade 4. The ultrafine-grained microstructure was produced by equal-channel angular pressing (ECAP) technique by using a Conform scheme and was characterized by a mean grain size of d=0.3 μm and non-equilibrium grain boundaries. The ultrafine-grained structure was found to be stable up to 400°C. The excellent thermal stability was attributed to a strain-ageing, i.e., the enhanced diffusion of interstitial solutes resulting in a formation of solute atmospheres at/near grain boundaries and dislocations. At 450–500°C, a rapid growth of strain-free grains was observed to occur. This process eliminated severely-deformed microstructure and gave rise to abrupt material softening. A further increase of the annealing temperature above 600°С resulted in precipitation of lenticular dispersoids as well as iron-rich globular β-particles. This surprising phenomenon promoted a subtle hardening effect.

scholarly journals Structural Nanocomposite Fabrication from Self-Assembled Choline Chloride Modified Kaolinite into Poly(Methylmethacrylate)

2019 ◽  
Vol 3 (3) ◽  
pp. 83 ◽  
Author(s):  
Dipti Saha ◽  
Mithun Kumar Majumdar ◽  
Ajoy Kumar Das ◽  
A.M. Sarwaruddin Chowdhury ◽  
Md. Ashaduzzaman
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Materials Science ◽  
Choline Chloride ◽  
Testing Machine ◽  
Attenuated Total Reflection ◽  
Nanocomposite Films ◽  
Pmma Film ◽  
Nanoscale Particles ◽  
Self Assembled

Composite materials produced from indigenous nanoscale particles and synthetic polymers have created demand in the field of nanoscience and technology. Layered silicates are potential candidates for reinforcing the properties of composites. Here, we report the fabrication of nanocomposites using poly(methylmethacrylate) (PMMA) as the matrix and the Bijoypur clay of Bangladesh known as kaolinite (200–250 nm) as the filler via solution casting. Kaolinite was first modified using choline chloride to prepare core-shell particles through a precipitation technique and was used for self-assembled nanocomposite films preparation. A series of nanocomposites films using 0, 1, 3, 5 and 10% (w/w) modified kaolinite was prepared. The neat PMMA and nanocomposite films were characterized by attenuated total reflection infra-red (ATR-IR) spectroscopy and X-ray diffraction (XRD) techniques. The mechanical properties, thermal stability, and morphology of the films were investigated using a universal testing machine (UTM), a thermal gravimetric analyzer (TGA), and a scanning electron microscope (SEM). The nanocomposite films exhibited better mechanical properties and thermal stability than neat PMMA film. Development of such structural nanocomposite materials using naturally occurring nanoscale particles would play a crucial role in the field of materials science for packaging applications and separation technology.

Olefin Metathesis–Based Chemically Recyclable Polymers Enabled by a Fused-Ring Monomer

2020 ◽  
Author(s):  
Junpeng Wang ◽  
Devavrat Sathe ◽  
Junfeng Zhou ◽  
Hanlin Chen ◽  
Hsin-Wei Su ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Ring Opening ◽  
Strain Energy ◽  
Decomposition Temperature ◽  
Excellent Thermal Stability ◽  
Fused Ring ◽  
Promising Solution ◽  
Sustainable Materials ◽  
Tunable Mechanical Properties

Abstract A promising solution to address the challenges in plastics sustainability is to replace current polymers with chemically recyclable ones that can depolymerise into their constituent monomers for circular use of materials. Despite the progress, few depolymerisable polymers exhibit the excellent thermal stability and strong mechanical properties of traditional polymers. Here we report a series of chemically recyclable polymers that show excellent thermal stability (decomposition temperature > 370 ºC) and tunable mechanical properties. The polymers are formed via ring-opening metathesis polymerisation of cyclooctene with a trans-cyclobutane installed at the 5,6-positions. The additional ring converts the non-depolymerisable polycyclooctene into a depolymerisable polymer by reducing the ring strain energy in the monomer (from 8.2 kcal/mol in unsubstituted cyclooctene to 4.9 kcal/mol in the fused ring). The fused-ring monomer enables a broad scope of functionalities to be incorporated, providing access to chemically recyclable elastomers and plastics that show promise as next-generation sustainable materials.

THERMAL STABILITY OF HELIUM BUBBLES IN NANOCRYATALLINE GOLD PREPARED BY GAS DEPOSITION METHOD

2010 ◽  
Vol 24 (01n02) ◽  
pp. 51-56
Author(s):  
TAKASHI INANMI ◽  
MAMORU KOBIYAMA ◽  
HIROSHI MAETA ◽  
MASATO SASASE ◽  
NORITO ISHIKAWA ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Grain Size ◽  
Grain Boundaries ◽  
Pure Gold ◽  
Deposition Method ◽  
Thermal Stabilities ◽  
Helium Bubbles ◽  
Transmission Electron ◽  
Thermal Stability Of

Specimens of nanocrystalline pure gold were prepared by the gas deposition method. The formation of helium bubbles in the specimens and their annealing behavior were studied in order to confirm their effect on thermal stabilities of grain size and mechanical properties. The specimens with 10-25nm mean grain size were analyzed by transmission electron microscopy and X-ray diffraction methods. Spherical helium bubbles, about 5nm in diameter, were formed, the same as in the case of helium ion implantation. After annealing at 573K for 1h in vacuum, most of the bubbles had not disappeared and some were trapped at the grain boundaries. Larger numbers of bubbles were trapped at grain boundaries in the specimens with high thermal stability than for low thermal stability specimens. Helium bubbles trapped at grain boundaries can be considered as local barriers to grain growth and to contribute to thermal stability of mechanical properties.

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