Grain-Size Stability and Microhardness of Copper-Fullerene Nanocomposites

1994 ◽  
Vol 351 ◽  
Author(s):  
R.L. Holtz ◽  
E.V. Barrera ◽  
J. Milliken ◽  
V. Provenzano
Keyword(s):  
Pure Copper ◽  
Columnar Growth ◽  
Low Concentrations ◽  
Heat Treated ◽  
Submicron Scale ◽  
Size Stability ◽  
Scale Granularity ◽  
Vicker’S Microhardness ◽  
Grain Size Stability ◽  
Thermal Stability Of

ABSTRACTNanocomposites of copper with low concentrations of dispersed fullerenes were synthesized by simultaneous sputtering of copper and sublimation of fullerenes. Postdeposition heat treatments at 400 and 800 °C were performed to assess the thermal stability of the microstructure and the effect on the Vicker's microhardness. The as-deposited copperfullerene composite has submicron-scale granularity, in contrast to pure copper which has conventional columnar growth. Grain growth in the heat-treated fullerene-containing specimens is suppressed and the microhardness enhanced relative to pure copper.

INCONEL ALLOY 718SPF

Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  
Keyword(s):  
Base Alloy ◽  
Low Flow ◽  
Inconel Alloy ◽  
Gamma Prime ◽  
Size Stability ◽  
Super Plastic ◽  
Plastic Forming ◽  
Super Plastic Forming ◽  
Grain Size Stability ◽  
Prime Phase

Abstract INCONEL alloy 718SPF is an age-hardenable austenitic material whose strength is largely dependent on the precipitation of a gamma prime phase following heat treatment. The base alloy, however, possesses two-essential characteristics for super-plastic forming; grain size stability over time and temperature; and a combination of low flow stress and significant ductility. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties as well as creep and fatigue. It also includes information on low and high temperature performance. Filing Code: Ni-471. Producer or source: Inco Alloys International Inc.

Microstructure and thermal stability of amorphous materials in the GeS2−La2S3 system

1991 ◽  
Vol 6 (12) ◽  
pp. 2694-2700 ◽  
Author(s):  
Prashant N. Kumta ◽  
Subhash H. Risbud
Keyword(s):  
Thermal Stability ◽  
Amorphous Materials ◽  
Fiber Optic ◽  
Molecular Level ◽  
Infrared Region ◽  
Mid Infrared ◽  
Heat Treated ◽  
Stable Glasses ◽  
Microstructural Studies ◽  
Thermal Stability Of

GeS2 is known to be a good chalcogenide glass former with a transmission cutoff at 11 μm and has been studied for fiber optic application in the mid infrared region. The rare earth sulfides, oxysulfides, and oxides (La–Er) form reasonably good and stable glasses when mixed with chalcogenides such as Ga2S3. In this work, glass formation was studied in the GeS2−La2S3 system. Two compositions containing 60 mol % and 92.5 mol % GeS2, respectively, were analyzed, and the effects of composition on the microstructure and thermal stability of these glasses were investigated. Microstructural studies were conducted on the as-prepared and heat-treated glasses using TEM and SEM/EDXA. Glasses rich in GeS2 exhibited primary (6–88 nm) and secondary (3–13 nm) phase separation at the molecular level. Differential thermal analysis performed on these glasses indicated glass transition temperatures (Tg) of 510 °C and 420 °C for the two compositions studied. The glasses were stable and the (Tg) was observed to decrease with increasing contents of GeS2 in these glasses.

Structure and Thermal Stability of Cu after Severe Plastic Deformation

2010 ◽  
Vol 297-301 ◽  
pp. 1312-1321 ◽  
Author(s):  
Vladimir V. Popov ◽  
A.V. Stolbovkiy ◽  
E.N. Popova ◽  
V.P. Pilyugin
Keyword(s):  
Thermal Stability ◽  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
High Pressure Torsion ◽  
Pure Copper ◽  
Nanocrystalline Structure ◽  
Transmission Electron ◽  
Evolution Of Structure ◽  
Stability Of Structure ◽  
Thermal Stability Of

Evolution of structure of high-purity and commercially pure copper at severe plastic deformation (SPD) by high pressure torsion (HPT) at room temperature and in liquid nitrogen has been studied by transmission electron microscopy (TEM) and measurements of microhardness. Thermal stability of structure obtained by HPT has been investigated. Factors preventing from obtaining nanocrystalline structure in Cu are analyzed and possible ways of their overcoming are discussed.

scholarly journals Effects of aluminum sulfate soaking pretreatment on dimensional stability and thermostability of heat-treated wood

2020 ◽  
Author(s):  
Lijie Qu ◽  
Zhenyu Wang ◽  
Jing Qian ◽  
Zhengbin He ◽  
Songlin Yi
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Thermal Degradation ◽  
Structural Changes ◽  
Aluminum Sulfate ◽  
Treated Wood ◽  
Treatment Temperature ◽  
Chinese Fir ◽  
Heat Treated ◽  
Thermal Stability Of

Abstract Acidic aluminum sulfate hydrolysis solutions can be used to catalyze the thermal degradation of wood in a mild temperature environment, and thus reduce the temperature required for heat treatment process. To improve the dimensional and thermal stability of Chinese fir during heat treatment at 120 °C, 140 °C and 160 °C, this study investigated the effects of soaking pretreatment with 5%, 10% and 15% aluminum sulfate on the chemical and structural changes of the heat-treated Chinese fir. The results indicated that the samples treated at 15% aluminum sulfate concentration and 160 °C heat treatment achieved the best dimensional and thermal stability. Chemical analyses by Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) indicated that the catalysis of aluminum sulfate resulted in degradation of hemicelluloses during the heat treatment, and an increase in the soaking concentration and heat treatment temperature also affected the thermal degradation of celluloses. The scanning electron microscope (SEM) and mass changes test results proved that the hydrolyzed aluminum flocs mainly adhered to the inner wall of the wood tracheid as spherical precipitates, and when the soaking concentration reached 10% and 15%, a uniform soaking effect could be achieved. The thermogravimetric (TG) analysis revealed the soaking pretreatment effectively improved the thermal stability of the heat-treated wood by physically wrapping and promoting the formation of a carbon layer on the wood surface during heat treatment. Thus, aluminum sulfate soaking pretreatment exerted a great effect on the dimensional and thermal stability of wood, allowing heat treatment to be performed at a lower temperature.

Chemical and Thermal Stability of Multiple Ions Doped Non-Stoichiometric Nanoapatite Heat-Treated in CO2 and Air Atmospheres

2014 ◽  
Vol 925 ◽  
pp. 77-81
Author(s):  
K. Jamuna Thevi ◽  
Mohammed Rafiq Abdul Kadir ◽  
Hendra Hermawan
Keyword(s):  
Thermal Stability ◽  
Nanocrystalline Phase ◽  
Secondary Phases ◽  
Wet Precipitation ◽  
Carbonate Ions ◽  
Precipitation Technique ◽  
Heat Treated ◽  
Phase Pure ◽  
20 Nm ◽  
Thermal Stability Of

Nanostructured apatite has been widely used as a bone substitute material due to its close resemblance to human bone mineral. To further mimic biological apatites, multiple ions doped non-stoichiometric nanoapatite has been studied. A nanosized apatite (NAp-2) containing Mg (1.09 wt%), Na (0.15 wt%), K (0.008 wt%) and CO32- (5.18 wt%) was synthesized by a wet precipitation technique. The presence of these ions in NAp-2 was detected using ICP. Broad diffraction peaks of XRD results indicated the presence of nanocrystalline phase pure NAp-2. The primary particle size of the resulted powder was ~ 20 nm, typical of bone crystal size, estimated using Scherrers equation. Based on CHN results, the NAp-2 powders showed a total loss of 51 and 78% of carbonate ions when heat-treated at 900°C in both CO2 and air atmospheres, respectively. This indicates that the heat-treatment in CO2 flux has reduced the carbonate ions lost from the NAp-2. A highly crystalline HA phase was formed in the ionic doped NAp-2 without secondary phases, indicating a thermal stability of this powder at 900°C in CO2 and air atmospheres. Thus, this study demonstrated that a phase pure multiple ions doped nanoapatite was synthesized using a wet precipitation technique.

scholarly journals EFFECT OF PROCESSING CONDITION AND COMPOSITION ON THE MICROHARDNESS OF Cu-(2.5-10)vol.%Al2O3 NANOCOMPOSITE POWDER PARTICLES PRODUCED BY HIGH ENERGY MECHANICAL MILLING

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2308-2313 ◽  
Author(s):  
AAMIR MUKHTAR ◽  
DELIANG ZHANG ◽  
CHARLIE KONG ◽  
PAUL MUNROE
Keyword(s):  
Dislocation Density ◽  
Mechanical Milling ◽  
Annealing Temperature ◽  
Processing Condition ◽  
High Energy ◽  
Composite Powders ◽  
Heat Treated ◽  
Powder Particles ◽  
Nanocomposite Powders ◽  
Thermal Stability Of

Nanostructured Cu -(2.5-10 vol. %) Al 2 O 3 nanocomposites were produced using high energy mechanical milling. For the as-milled Cu - Al 2 O 3 composite powder particles having Al 2 O 3 volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al 2 O 3 nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu - Al 2 O 3 composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al 2 O 3 composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu -(2.5-10) vol. % Al 2 O 3 nanocomposite powders.

scholarly journals Polyol-Mediated Synthesis of Zinc Oxide Nanorods and Nanocomposites with Poly(methyl methacrylate)

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Alojz Anžlovar ◽  
Zorica Crnjak Orel ◽  
Ksenija Kogej ◽  
Majda ¦igon
Keyword(s):  
Methyl Methacrylate ◽  
Storage Modulus ◽  
Zno Nanorods ◽  
Mechanical Analysis ◽  
Zinc Oxide Nanorods ◽  
Poly Methyl Methacrylate ◽  
Low Concentrations ◽  
Oxide Nanorods ◽  
End Capping ◽  
Thermal Stability Of

ZnO nanorods (length 30–150 nm) were synthesized in di(ethylene glycol) using Zn(CH3COO)2as a precursor andpara-toluene sulphonic acid, p-TSA, as an end-capping agent. Increasing the concentration of p-TSA above 0.1 M causes the reduction of the ZnO length. Nanocomposites with poly(methyl methacrylate) were prepared using unmodified nanorods. They enhanced the UV absorption of nanocomposites (∼98%) at low ZnO concentrations (0.05–0.1 wt.%), while visible light transparency was high. At concentrations of 1 wt.% and above, nanorods enhanced the thermal stability of nanocomposites. At low concentrations (0.05–0.1 wt.%), they increased the storage modulus of material and shiftedTgtowards higher temperatures as shown by dynamic mechanical analysis, DMA, while at higher concentrations (1.0 wt.%) this effect was deteriorated. DMA also showed that spherical ZnO particles have a more pronounced effect on the storage modulus andTgthan nanorods.

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