scholarly journals EFFECTS OF PREFERRED ORIENTATION AND GRAIN SIZE ON DIMENSIONAL STABILITY OF URANIUM ON THERMAL CYCLING AND IRRADIATION. Final Report-Metallurgy Program 5.1.7

1956 ◽  
Author(s):  
H. H. Chiswik
Keyword(s):  
Grain Size ◽  
Thermal Cycling ◽  
Dimensional Stability ◽  
Preferred Orientation ◽  
Final Report

scholarly journals Texture of Polar Firn for Remote Sensing

1987 ◽  
Vol 9 ◽  
pp. 1-4 ◽  
Author(s):  
R.B. Alley
Keyword(s):  
Remote Sensing ◽  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Anisotropic Medium ◽  
Preferred Orientation ◽  
Remotely Sensed Data ◽  
Horizontal Orientation ◽  
Prolate Spheroids ◽  
Grain Surface

Knowledge of the texture of polar firn is necessary for interpretation of remotely sensed data. We find that dry polar firn is an irregularly stratified, anisotropic medium. Grains in firn may be approximated as prolate spheroids with average axial ratios as high as 1.2 or greater and with a preferred orientation of long axes clustered around the vertical. Such elongate grains are preferentially bonded near their ends into vertical columns, so that grain bonds show a preferred horizontal orientation. The grain-size distribution is similar in most firn and the normalized distribution is stationary in time, but the distribution is somewhat different in depth hoar. Fluctuations of firn properties are large near any depth, but decrease with increasing depth. With increasing depth, anisotropy of surfaces decreases, bond size relative to grain size decreases slightly, and number of bonds per grain and fraction of total grain surface in bonds increase. Grain size increases linearly with age below 2 to 5 m, but increases more rapidly in shallower firn.

scholarly journals Characterization and Alumina Leachability of 12CaO·7Al2O3with Different Holding Times

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hui-lan Sun ◽  
Bo Wang ◽  
Jian-xin Zhang ◽  
Shu-feng Zong
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Lattice Constant ◽  
Preferred Orientation ◽  
Holding Time ◽  
Synthesis Time ◽  
Rate Of Increase ◽  
Average Grain Size ◽  
Long Time ◽  
Scherrer Formula

The effect of synthesis time on phase compositions, lattice constant, average grain size, preferred orientation, and surface morphology of 12CaO·7Al2O3synthesized at 1500°C was analyzed by XRD and SEM. The results indicate that the main phase of samples synthesized is 12CaO·7Al2O3when holding time is over 30 min. The lattice constant increases and the preferred orientation decreases as synthesis time prolongs. The average grain size of samples is about 59 nm calculated by Scherrer formula, and it does not change with synthesis time. The synthesis time affects the micromorphology of samples greatly. There are more and bigger holes in samples synthesized for long time. The aspects mentioned above cause the alumina leaching ratio of 12CaO·7Al2O3to increase with the prolonging of synthesis time, but the rate of increase drops.

New lattice preferred orientation(LPO) of amphibole experimentally found in simple shear

2020 ◽  
Author(s):  
Junha Kim ◽  
Haemyeong Jung
Keyword(s):  
Grain Size ◽  
High Pressure ◽  
Shear Strain ◽  
Seismic Anisotropy ◽  
Preferred Orientation ◽  
Shear Direction ◽  
High Shear ◽  
Type Iv ◽  
Lower Shear ◽  
Lattice Preferred Orientation

<p>The lattice preferred orientation(LPO) of amphibole has a large effect on seismic anisotropy in the crust. Previous studies have reported four LPO types (I–IV) of amphibole, but the genesis of type IV LPO, which is characterized by [100] axes aligned in a girdle subnormal to the shear direction, is unknown. In this study, shear deformation experiments on amphibolite were conducted to find the genesis of type IV LPO at high pressure (0.5 GPa) and temperature (500–700 °C). The type IV LPO was found under high shear strain (γ > 3.0) and the sample exhibited grains in a range of sizes but generally smaller than the grain size of samples with lower shear strain. The seismic anisotropy of type IV LPO is lower than in types I-III. The weak seismic anisotropy of highly deformed amphibole could explain weak seismic anisotropy observed in the middle crust.</p>

A Thermal Cycling Route for Processing Nano-grains in AISI 316L Stainless Steel for Improved Tensile Deformation Behaviour

2016 ◽  
Vol 66 (5) ◽  
pp. 529 ◽  
Author(s):  
Tarun Nanda ◽  
B. Ravi Kumar ◽  
Vishal Singh
Keyword(s):  
Grain Size ◽  
Thermal Cycling ◽  
Thermal Cycle ◽  
Strain Energy ◽  
316L Stainless Steel ◽  
Tensile Deformation ◽  
Cold Deformation ◽  
Aisi 316L ◽  
Stored Energy ◽  
Aisi 316L Stainless Steel

<p>The present work significantly improved the mechanical strength of AISI 316L stainless steel by producing nano-sized grains. Steel was subjected to cold rolling followed by repetitive thermal cycling to produce ultra-fine/ nano-sized grains. The optimum processing parameters including extent of cold deformation, annealing temperature for thermal cycling, soaking period during each thermal cycle, and number of thermal cycles were determined through a systematic step-by-step procedure. After conducting thermal cycling under optimum conditions, a significant amount of grain size reduction was achieved. The effect of nano-sized grains on tensile deformation behavior was analysed. High cold deformation resulted in increased amount of stored strain energy. The stored strain energy accelerated the re-crystallisation kinetics during the thermal cycling process. Every thermal cycle resulted in irregular dispersal of stored energy. This irregular dispersal of stored energy favoured recrystallisation rather than grain growth and led to refinement of grains, in the absence of strain induced martensite. Repetitive thermal cycling promoted grain refinement and resulted in very significant grain size reduction with resultant grain size in the range of 800–1200 nm as compared to initial size of 90–120 μm. The resultant microstructure improved tensile strength by<br />106.8 per cent, from 590 MPa to 1220 MPa.</p>

Effects of C/Si Ratio on the Structure of β-SiC Film by Halide CVD

2014 ◽  
Vol 616 ◽  
pp. 227-231 ◽  
Author(s):  
Ming Xu Han ◽  
Wei Zhou ◽  
Ding Heng Zheng ◽  
Rong Tu ◽  
Song Zhang ◽  
...  
Keyword(s):  
Grain Size ◽  
Deposition Rate ◽  
Total Pressure ◽  
Deposition Temperature ◽  
Preferred Orientation ◽  
Carrier Gas ◽  
Sic Film ◽  
Sic Films

Thick (over 1 mm) β-SiC films were deposited at a deposition temperature of 1823 K and a total pressure of 4 kPa by halide CVD using SiCl4 and CH4as precursors, and H2 as carrier gas. The maximum deposition rate was 1125 μm h−1. The SiC films showed strong (220) preferred orientation. The grain size increased from 20 to 100 μm with increasing C/Si ratio.

Effect of Annealing and Passivation on the Electromigration and Linewidth Dependence

1995 ◽  
Vol 391 ◽  
Author(s):  
R.O. Carnes ◽  
C.H. Lee ◽  
P.T. Keating ◽  
E.M. Barrall II ◽  
B.R. York ◽  
...  
Keyword(s):  
Grain Size ◽  
Failure Modes ◽  
Preferred Orientation ◽  
Film Stress ◽  
X Ray Diffraction ◽  
Thermal Budget ◽  
Geometric Confinement ◽  
The Impact ◽  
The Relationship ◽  
Post Deposition

AbstractContinued miniaturization of conductor geometry below 0.5μm has by a concomitant decrease in Al deposition temperature, typically below 300°C. The degree of reliability exhibited by these films is strongly dependent on the grain size distribution and metallurgical configuration. This investigation focuses on the impact of post-deposition processing on changes in conductor microstructure and electromigration for films deposited at low temperature. AlCu(l%)Si(l%) was deposited at 300°C on PECVD phosphosilicate glass. The impact of post-deposition thermal budget on the as deposited grain size and distribution, preferred orientation and stress/strain states were analyzed using scanning electron microscopy, X-Ray diffraction and bending beam technique, respectively. These characteristics were also measured on unpassivated films subjected to the same thermal budget as SiO2 passivated films so that the geometric confinement and Al-SiO2 surface interaction could be quantified. Electromigration characteristics were measured for linewidths in the range W=1.0μm to W=10μm, for passivated and unpassivated films. A direct correlation between passivation and grain size was observed for both failure modes. This paper will also discuss the relationship between film stress and preferred orientation, the observed failure modes and their linewidth dependence.

Dimensional stability of adsorbents subjected to thermal cycling

Adsorption ◽  
2013 ◽  
Vol 20 (2-3) ◽  
pp. 409-416
Author(s):  
Mark W. Ackley ◽  
Steven J. Pontonio
Keyword(s):  
Thermal Cycling ◽  
Dimensional Stability

Effects of Substrate Bias Voltage on the Microstructure of Cr-Al-N Coatings

2008 ◽  
Vol 373-374 ◽  
pp. 167-171 ◽  
Author(s):  
Ming Zhu ◽  
Shu Wang Duo ◽  
Tian Peng Li ◽  
Mei Shuan Li ◽  
Yan Chun Zhou
Keyword(s):  
Grain Size ◽  
Bias Voltage ◽  
Failure Load ◽  
Lattice Parameter ◽  
Preferred Orientation ◽  
Negative Bias ◽  
Substrate Bias ◽  
Reactive Magnetron ◽  
Negative Bias Voltage ◽  
Substrate Bias Voltage

Cr-Al-N coatings with the thickness of about 2 μm have been prepared by a reactive magnetron sputtering method. The effects of substrate negative bias voltage (VB) on the microstructure and critical failure load have been investigated as the VB varied from 0 to –150 V. With VB increasing, grain size, lattice parameter and microstrain increase. (111) preferred orientation dominates in the coatings deposited under 0 and –50 V, while a (200) preferred orientation developed when VB further raised. The reasons for these variation caused by VB are discussed.

Effects of Mg and Si in Al Matrix on Dimensional Stability of SiCp/Al Composites during Temperature Change

2013 ◽  
Vol 631-632 ◽  
pp. 335-340
Author(s):  
Ai Hua Zou ◽  
Xian Liang Zhou ◽  
Duo Sheng Li ◽  
Xiao Zhen Hua
Keyword(s):  
Thermal Cycling ◽  
Dimensional Stability ◽  
Residual Strain ◽  
Small Range ◽  
Absolute Value ◽  
Dimensional Variation ◽  
Si Content ◽  
Cumulative Residual ◽  
Mg Content ◽  
Al Matrix

In this paper, based on the parameters of cumulative residual strain(CRS), the effects of different contents of Mg and Si elements in Al matrix on the dimensional stability of SiCp/Al composites was investigated and analyzed in the temperature interval of 25～400°C. Results show that，with the increasing of Si content in Al matrix, the CRS fluctuates only in a small range of strain, adding Si in Al matrix is beneficial to the dimensional stability of the composites, which can be improved through pre-thermal cycling; with the increasing of Mg content in Al matrix, the absolute value of negative CRS of the composites becomes smaller at the beginning and then turns positive, adding Mg in Al matrix causes the composites expand after several thermal cycling, it is not good to the dimensional stability of the composites and is quite impossible to be improved by pre-thermal cycling. Besides, the CRS in thermal cycling is mainly caused by the plastic relaxation, which results in the irreversible dimensional variation of about 10-5~10-4.

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