scholarly journals Microstructure Characterization of Ni-Based Alloys for Packaging Application upon Long-Term Heat Treatment

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1159
Author(s):  
Jianbing Ren ◽  
Yilong Ma ◽  
Kejian Li
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Grain Size ◽  
Temperature Treatment ◽  
Working Environment ◽  
High Temperature Treatment ◽  
Surface Corrosion ◽  
Two Samples ◽  
Mo Content

In this study, an investigation was conducted to examine two types of Ni-based alloys upon long-term heat treatment and compare their grains, surface corrosion layers and microhardness values. The working environment of the tested samples was a temperature of 1000 °C for 5000 h. Two samples, respectively, contained low (~8 wt.%) and high (~16 wt.%) contents of Mo, and the low-Mo-content sample contained Nb (~4 wt.%) and other elements. The grains, precipitates, corrosion layers and microhardness values of the samples before and after heat treatment were determined by scanning electron microscopy, electron back-scattered diffraction, transmission electron microscopy, X-ray diffraction analysis and Vickers hardness tests. The results revealed that the grain was surprisingly stable in the sample with the higher Mo content; after heat treatment, the grain size was ~35 μm, which was similar to the grain size before heat treatment. Moreover, for the sample with the higher Mo content, the microhardness was found to be higher, especially after long-term high-temperature treatment, which is of great significance for the long service life of materials.

The effect of grain size on microstructure and stress relaxation in polycrystalline Y1Ba2Cu3O7−δ

1989 ◽  
Vol 4 (2) ◽  
pp. 248-256 ◽  
Author(s):  
T. M. Shaw ◽  
S. L. Shinde ◽  
D. Dimos ◽  
R. F. Cook ◽  
P. R. Duncombe ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Stress Relaxation ◽  
Optical Microscopy ◽  
Slow Cooling ◽  
Hierarchical Arrangement ◽  
Transmission Electron ◽  
Processing Variables

We have used transmission electron microscopy and optical microscopy to examine the effect that grain size and heat treatment have on twinning and microcracking in polycrystalline Y1Ba2Cu3O7−δ. It is shown that isothermal oxygenation heat treatments produce twin structures consisting of parallel twins, with a characteristic spacing that increases with increasing grain size. Slow cooling through the temperature range where the orthorhombic-to-tetragonal transformation induces twinning, however, produces a structure consisting of a hierarchical arrangement of intersecting twins, the scale of which appears to be independent of grain size. It is also shown that the microcracking induced by anisotropic changes in grain dimensions on cooling or during oxygenation can be suppressed if the grain size of the material is kept below about 1 μm. The results are examined in the light of current models for transformation twinning and microcracking and the models used to access the effect other processing variables such as oxygen content, doping or heat treatment may have on the microstructure of Y1Ba2Cu3O7−δ.

Reduction of hardseededness in mungbean by short duration high temperature treatment

1992 ◽  
Vol 32 (4) ◽  
pp. 483 ◽  
Author(s):  
BC Imrie
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Short Duration ◽  
Vigna Radiata ◽  
Pilot Trial ◽  
Rotating Cylinder ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Hot Plate ◽  
Hard Seeds

Seeds of 2 lines of mungbean (Vigna radiata), soft-seeded cv. Berken and HS23 with 34% hard seeds, were agitated on a hot plate to determine the effects of temperatures up to 200�C on hardseededness, germination and seed variability. The results of this experiment, combined with a pilot trial using a heated rotating cylinder, showed that the temperature of 175�C for 30 s was the optimum treatment to produce seeds suitable for sprouting. This heat treatment reduced hardseededness from 34 to 1%, increased germination from 64 to 96%, and did not increase the percentage of dead seeds.

scholarly journals Long-term consequences of high incubation temperature in a wild bird population

2016 ◽  
Vol 12 (4) ◽  
pp. 20160087 ◽  
Author(s):  
Andreas Nord ◽  
Jan-Åke Nilsson
Keyword(s):  
High Temperature ◽  
Body Mass ◽  
Incubation Temperature ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Bird Population ◽  
Biologically Relevant ◽  
Faster Development ◽  
Incubation Temperatures

Because incubation by birds is energetically costly, parents frequently trade off investment in incubation against self-maintenance. This can be manifested by a reduction in incubation temperature, which comes at high somatic costs for nestlings. The extent to which these costs constrain fitness is poorly understood. We incubated wild blue tit clutches at three biologically relevant temperatures and subsequently recorded winter survival and survival to the breeding season. Fledglings from the coldest treatment (35.0°C) survived less well than other fledglings, but the proportion of winter and breeding survivors did not differ significantly between treatments. However, survival probability in both seasons increased with body mass at fledging in birds from low and mid incubation temperatures, but decreased with fledging body mass in the high-temperature treatment. Mid-temperature nestlings were heavier as adults, weighing 7% more than low- and high-temperature survivors. Thus, high incubation temperature can be beneficial in the short term, but costs of accelerated embryonic development may equal those of protracted development in the long term. Such hidden consequences of faster development could maintain natural selection for average incubation temperature.

A modified ultra high temperature treatment for reducing microbial lipolysis in stored milk

1987 ◽  
Vol 54 (2) ◽  
pp. 275-282 ◽  
Author(s):  
Anthony R. Bucky ◽  
Patrick R. Hayes ◽  
David S. Robinson
Keyword(s):  
Heat Treatment ◽  
Fatty Acids ◽  
High Temperature ◽  
Free Fatty Acids ◽  
Storage Period ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Viable Cells ◽  
Whole Milk ◽  
Ultra High Temperature

SummaryCultures ofPseudomonasP46 grown in whole milk to contain ∼ 2 × 107or 1 × 108viable cells ml−1before ultra high temperature (UHT) treatment (140°C for 5 s) demonstrated near linear increases in the concentration of short-chain free fatty acids (FFA) during storage at 20°C. However with 5 × 106cells ml−1before UHT heat treatment there was no detectable increase in these FFA levels over a 6-month storage period. A novel heat treatment (140°C for 5 s followed by 60°C for 5 min) reduced the rate of production of volatile FFA to < 10% of the rates achieved after the normal UHT treatment.

Effect of Structure on the Mechanical Properties of PAN-Based Carbon Fibers during Graphitization

2011 ◽  
Vol 686 ◽  
pp. 770-777 ◽  
Author(s):  
Hao Xiao ◽  
Yong Gen Lu ◽  
Xian Ying Qin ◽  
Ya Wen
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fiber Surface ◽  
Total Porosity ◽  
Interlayer Spacing ◽  
Temperature Treatment ◽  
Treatment Temperature ◽  
High Temperature Treatment ◽  
X Ray Diffraction ◽  
Crystallite Sizes

An investigation was conducted to determine the influence of high temperature treatment from 1600°C to 2800°C under stretching stress of 10MPa on PAN-based carbon fiber structure and physical properties. The tensile strength of fibers decreased from 4.5GPa to 2.97GPa with increasing treatment temperature up to 2800°C，while the modulus of fibers increased from 230GPa to 375GPa The texture in the longitudinal surface of fibers through heat treatment was characterized using a scanning electron microscopy. The contours of fiber surface became accidented with gaps becoming deeper as temperature increased. It has been observed that both the crystallite sizes (La, Lc) and the degree of preferred orientation increasd, while the crystallite interlayer spacing (d002) decreased by X-ray diffraction analysis with increasing heat-treatment temperature. The total porosity of fibers decreased from 21.01% to 15.09% and while the density of fibers increased from 1.720g/cm-3to1.886 g/cm-3with increasing heat-treatment. In addition, the relationship between mechanical properties and structure of variants was also explored in detail.

Computer Modeling of the Process of Synthesis of Porous Glass-Composite Materials

2019 ◽  
Vol 945 ◽  
pp. 975-980
Author(s):  
L.A. Yatsenko ◽  
Elena A. Yatsenko ◽  
B.M. Goltsman
Keyword(s):  
Experimental Data ◽  
Heat Treatment ◽  
Computer Simulation ◽  
Pore Formation ◽  
Laboratory Experiments ◽  
Foam Glass ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Glass Composite ◽  
Computer Simulation Program

The operational properties of thermal insulation materials directly depend on their structure. The processes of pore formation occur inside the material after high-temperature treatment, which makes their studying more expensive and complicated. On the basis of experimental data, a computer simulation program for the process of pore formation has been developed, which makes it possible to simulate the processes of changing the structure of foam glass during heat treatment without repeated laboratory experiments.

Study on Electrospun-Membrane-Based Filter to Rapidly Remove Reactive Yellow 2 from Wastewater

2013 ◽  
Vol 726-731 ◽  
pp. 707-711
Author(s):  
Wen Peng Zhang ◽  
Da Yong Wu ◽  
Ya Kun Wang
Keyword(s):  
Electron Microscopy ◽  
Mesoporous Silica ◽  
Adsorption Capacity ◽  
Temperature Treatment ◽  
High Temperature Treatment ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Electrospun Membrane ◽  
Transmission Electron ◽  
Prepared Material

Uniform highly ordered mesoporous silica nanofiber membrane was successfully prepared onto copper mesh via coaxial electrospinning combining with the solvent evaporation and extraction induced surfactant assembly process. After a high temperature treatment and amination, it was employed to remove reactive yellow 2 (RY2) in wastewater showing remarkable adsorption capacity. The maximum adsorption capacity can reach up to 371.7 mg/g. The structural properties of synthesized mesoporous silica were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier transform infrared spectrum (FTIR). And the adsorption behavior of prepared material was analyzed through three kinds of isotherm models.

Heat Treatment of Nanocrystalline Al2O3-Zr02

1996 ◽  
Vol 457 ◽  
Author(s):  
Bridget M. Smyser ◽  
Jane F. Connelly ◽  
Richard D. Sisson ◽  
Virgil Provenzano
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Grain Size ◽  
Monoclinic Phase ◽  
Phase Distribution ◽  
Critical Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated

ABSTRACTThe effects of grain size on the phase transformations in nanocrystalline ZrO2-Al2O3 have been experimentally investigated. Compositions from 10 to 50 vol% Al2O3 in ZrO2 were obtained as a hydroxide gel. The powders were then calcined at 600 °C for 17 hours and heat treated at 1100 °C for 24 and 120 hours and at 1200 °C for 2 hours. The phase distribution and grain size were determined using x-ray diffraction and transmission electron microscopy. The initial grain size after calcining was 8–17 nm. It was determined that the critical ZrO2 grain size to avoid the tetragonal to monoclinic phase transformation on cooling from 1100 °C was between 17 and 25 nm. Samples containing 50% Al2O3 maintained a grain size below the critical size for all times and temperatures. The 30% Al2O3 samples showed the same behavior in all but one heat treatment. The remainder of the samples showed significant grain growth and at least partial transformation to the monoclinic phase.

Transmission Electron Microscopy Study of Microstructural Evolution in Nanograined Ni-Ti Microwires Heat Treated by Electric Pulse

2011 ◽  
Vol 172-174 ◽  
pp. 682-687 ◽  
Author(s):  
Remi Delville ◽  
Benoît Malard ◽  
Jan Pilch ◽  
Petr Šittner ◽  
Dominique Schryvers
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Electric Pulse ◽  
Microscopy Study ◽  
Dislocation Slip ◽  
Transmission Electron ◽  
Heat Treated ◽  
Conventional Heat Treatment

Transmission electron microscopy and mechanical testing were employed to investigate the evolution of microstructure and functional superelastic properties of 0.1mm diameter as-drawn Ni-Ti wires subjected to a non-conventional heat treatment by controlled electric pulse current. This method enables a finer control of the recovery and recrystallisation processes taking place during the heat treatment and accordingly a better control on the final microstructure. The best functional properties were obtained for heat-treated Ni-Ti wires having a nanograined microstructure (20-50 nm) partially recovered through polygonization and partially recrystallized. Such microstructure is highly resistant against dislocation slip upon cycling, while microstructures annealed for longer time and showing mostly recrystallized grains were prone to dislocation slip, particularly as the grain size exceeds 100 nm. The density of dislocation defects increased significantly with increasing grain size of the microstructure. The activity of three <100>/{011} slip systems was identified in the largest grains of 500-1200 nm. An additional mode of plastic deformation, {114} compound austenite twinning, was observed in the largest grains of fully recrystallized microstructures. It is proposed that dislocation slip (and possibly deformation twinning) occurring in superelastic cycling is coupled with the stress-induced martensitic transformation.

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