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.

Dynamic Mechanical Properties and Thermal Stability of PTT/POE/OMMT Nanocomposites

2011 ◽  
Vol 366 ◽  
pp. 306-309
Author(s):  
Ming Tao Run ◽  
Na Li ◽  
Bing Tao Xing ◽  
Meng Yao ◽  
Wen Zhou
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Dynamic Mechanical Properties ◽  
Thermal Gravimetric ◽  
Dynamic Mechanical ◽  
Thermal Gravimetric Analyzer ◽  
Transmission Electron ◽  
Reinforcing Agent ◽  
Thermal Stability Of

The dynamic mechanical properties, phase morphology and thermal stability of the poly(trimethylene terephthalate)/maleinized poly(octene-ethylene)/organo-montmorillonite nanocomposites (PTT/POE/OMMT) were investigated by using the thermodynamic mechanical analyzer (DMA), transmission electron microscopy (TEM) and thermal gravimetric analyzer (TGA), respectively. The results suggest that the modulus of elasticity of the PTT/POE/OMMT nanocomposite increases, and the glass transition temperature first slightly decreases and then increases with increasing OMMT content because that the TPP plays the role of plasticizer and OMMT plays the role of reinforcing agent. OMMT disperse evenly in the polymer matrix with most of the strip-like sheet morphology. The addition of the OMMT does not apparently affect the thermal stability of the PTT/POE/OMMT nanocomposite.

Abrasion Properties and Thermal Stabilities of Poly(vinyl chloride)/Diatomite Composites

2013 ◽  
Vol 833 ◽  
pp. 317-321 ◽  
Author(s):  
Feng Zhan ◽  
Nan Chun Chen ◽  
Xiao Hu Zhang ◽  
Bin Huang ◽  
Zhi Neng Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Vinyl Chloride ◽  
Abrasion Resistance ◽  
Flexural Modulus ◽  
Dynamic Mechanical Properties ◽  
Thermal Stabilities ◽  
Poly Vinyl Chloride ◽  
Thermal Stability Of ◽  
Properties Of Composites

Mechanical properties, abrasion properties, thermal stabilities, and dynamic mechanical properties of poly (vinyl chloride) (PVC)/diatomite composites with different diatomite content prepared by melting blending were investigated. The results indicated that mechanical properties of composites have different performance due to diatomite participation, and the flexural modulus was improved. With an increase in diatomite, the abrasion resistance and thermal stability of composites were improved. Furthermore, the E' and Tg of composites could be enhanced effectively with diatomite participation. The optimum combined properties of PVC/diatomite composite were obtained with the adding of 40 phr diatomite.

The Influence of the ECAP Temperature on Microstructure and Mechanical Properties of a Magnesium Alloy

2006 ◽  
Vol 503-504 ◽  
pp. 609-614 ◽  
Author(s):  
Olya B. Kulyasova ◽  
Rinat K. Islamgaliev ◽  
Nikolay A. Krasilnikov
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Transmission Electron Microscopy ◽  
Magnesium Alloy ◽  
Volume Fraction ◽  
Angular Pressing ◽  
Transmission Electron ◽  
Significant Difference ◽  
Thermal Stability Of

The influence of the equal channel angular pressing (ECAP) temperature (150-350oC) on microstructure of the AM60 magnesium alloy has been investigated using transmission electron microscopy. It was demonstrated that application of various ECAP regimes leads to significant difference in a grain size and volume fraction of precipitates in investigated material. Thermal stability of precipitates and correlation between microstructure and tensile strength are discussed.

scholarly journals Thermal Stability of Nanocrystalline Gradient Inconel 718 Alloy

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 53
Author(s):  
Jie Ding ◽  
Yifan Zhang ◽  
Tongjun Niu ◽  
Zhongxia Shang ◽  
Sichuang Xue ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Grain Size ◽  
Inconel 718 ◽  
Treatment Technique ◽  
Mechanical Grinding ◽  
Inconel 718 Alloy ◽  
Transmission Electron ◽  
Nickel Based Alloy ◽  
Energy Configurations ◽  
Thermal Stability Of

Gradient structures containing nanograins in the surface layer have been introduced into Inconel 718 (IN718) nickel-based alloy using the surface mechanical grinding treatment technique. The thermal stability of the gradient IN718 alloy was investigated. Annealing studies reveal that nanograins with a grain size smaller than 40 nm exhibited significantly better thermal stability than those with larger grain size. Transmission electron microscopy analyses reveal that the enhanced thermal stability was attributed to the formation of grain boundaries with low energy configurations. This study provides new insight on strategies to improve the thermal stability of nanocrystalline metals.

New Progress on Er-Containing Micro-Alloying Aluminum Alloys

2016 ◽  
Vol 877 ◽  
pp. 211-217 ◽  
Author(s):  
Xiao Lan Wu ◽  
Zuo Ren Nie ◽  
Sheng Ping Wen ◽  
Kun Yuan Gao ◽  
Hui Huang
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Grain Size ◽  
Aluminum Alloys ◽  
Core Shell ◽  
Alloying Element ◽  
Fine Dispersion ◽  
Comprehensive Performance ◽  
The Matrix ◽  
Thermal Stability Of

Erbium is an effective micro-alloying element in aluminum alloys and has been investigated intensively. Similar with the addition of Sc in aluminum alloys, nanosized L12-ordered Al3Er precipitates were formed coherently with the matrix in Er-containing micro-alloying aluminum alloys. Further, in the case of the addition of both Er and Zr, core-shell-structured Al3(ZrxEr1−x) precipitates, instead of Al3Er, were observed in a fine dispersion. Those thermally-stable precipitates can refine the grain size, minimize the segregation, homogenize the microstructure, enhance the strength, hinder the recrystallization, and thus improve the comprehensive performance of the aluminum alloys. This paper presents the effect of Er on the microstructure, mechanical properties and thermal stability of aluminum alloys. The research of some typical commercial aluminum alloys containing Er, is also reviewed here.

scholarly journals Chemical boundary engineering: A new route toward lean, ultrastrong yet ductile steels

2020 ◽  
Vol 6 (13) ◽  
pp. eaay1430 ◽  
Author(s):  
Ran Ding ◽  
Yingjie Yao ◽  
Binhan Sun ◽  
Geng Liu ◽  
Jianguo He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Grain Size ◽  
Grain Boundary ◽  
Carbon Steels ◽  
Metallic Materials ◽  
Grain Boundary Engineering ◽  
Design Strategies ◽  
Thermal Stability Of ◽  
Unique Chemical

For decades, grain boundary engineering has proven to be one of the most effective approaches for tailoring the mechanical properties of metallic materials, although there are limits to the fineness and types of microstructures achievable, due to the rapid increase in grain size once being exposed to thermal loads (low thermal stability of crystallographic boundaries). Here, we deploy a unique chemical boundary engineering (CBE) approach, augmenting the variety in available alloy design strategies, which enables us to create a material with an ultrafine hierarchically heterogeneous microstructure even after heating to high temperatures. When applied to plain steels with carbon content of only up to 0.2 weight %, this approach yields ultimate strength levels beyond 2.0 GPa in combination with good ductility (>20%). Although demonstrated here for plain carbon steels, the CBE design approach is, in principle, applicable also to other alloys.

Thermal stability of CaCO3/polyethylene (PE) nanocomposites

2019 ◽  
Vol 27 (7) ◽  
pp. 371-382
Author(s):  
S Sahebian ◽  
MT Hamed Mosavian
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Thermal Stability ◽  
Morphological Structure ◽  
Thermomechanical Analysis ◽  
Scanning Calorimetry ◽  
Weight Percentage ◽  
Transmission Electron ◽  
Crystallization Experiments ◽  
Thermal Stability Of

Calcium carbonate (CaCO3) nanoparticles in polymer matrix cause to improvement in polymer performance, including thermal stability and mechanical properties. The main goal of this article is to investigate the effect of different weight percentage of nanoparticles of CaCO3 on thermal stability and mechanical properties of polyethylene (PE) nanocomposites. The morphological structure of CaCO3 nanoparticles and nanocomposites was investigated by transmission electron microscopy and scanning electron microscopy. The thermal stability of PE and its nanocomposites was also determined by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and thermomechanical analysis. Nonisothermal crystallization experiments by DSC test showed that the incorporation of nanoparticles increased the crystallinity, glass transition temperature, and the effective energy barrier for crystallization process. Besides, degradation behavior was evaluated by TGA. The onset mass loss temperature shifted to higher value in the presence of nanoparticles.

scholarly journals Controlling the Thermal Stability of Kyanite-Based Refractory Geopolymers

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2903
Author(s):  
Juvenal Giogetti Nemaleu Deutou ◽  
Rodrigue Cyriaque Kaze ◽  
Elie Kamseu ◽  
Vincenzo M. Sglavo
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Strength ◽  
Treatment Temperature ◽  
Strength Development ◽  
Particle Sizes ◽  
Cold Setting ◽  
Thermal Stability Of ◽  
Geopolymer Composites ◽  
Refractory Composites

The present project investigated the thermal stability of cold-setting refractory composites under high-temperature cycles. The proposed route dealt with the feasibility of using fillers with different particle sizes and studying their influence on the thermo-mechanical properties of refractory geopolymer composites. The volumetric shrinkage was studied with respect to particle sizes of fillers (80, 200 and 500 µm), treatment temperature (1050–1250 °C) and amount of fillers (70–85 wt.%). The results, combined with thermal analysis, indicated the efficiency of refractory-based kyanite aggregates for enhancing thermo-mechanical properties. At low temperatures, larger amounts of kyanite aggregates promoted mechanical strength development. Flexural strengths of 45, 42 and 40 MPa were obtained for geopolymer samples, respectively, at 1200 °C, made with filler particles sieved at 80, 200 and 500 µm. In addition, a sintering temperature equal to 1200 °C appeared beneficial for the promotion of densification as well as bonding between kyanite aggregates and the matrix, contributing to the reinforcement of the refractory geopolymer composites without any sign of vitrification. From the obtained properties of thermal stability, good densification and high strength, kyanite aggregates are efficient and promising candidates for the production of environmentally friendly, castable refractory composites.

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