Irradiation-induced large bubble formation and grain growth in super nano-grained ceramic

2021 ◽  
Vol 41 (15) ◽  
pp. 7868-7877
Author(s):  
Yutong Zhang ◽  
Zhangyi Huang ◽  
Jianqi Qi ◽  
Zhe Tang ◽  
Lang Wu ◽  
...  
Keyword(s):  
Grain Growth ◽  
Bubble Formation ◽  
Large Bubble

Bubble formation, motion and interaction in a Hele-Shaw cell

1986 ◽  
Vol 173 ◽  
pp. 95-114 ◽  
Author(s):  
T. Maxworthy
Keyword(s):  
Ad Hoc ◽  
Bubble Formation ◽  
Bubble Surface ◽  
Large Bubble ◽  
Rise Velocity ◽  
Parallel Plates ◽  
Narrow Gap ◽  
Wide Range ◽  
Bubble Characteristics ◽  
Hele Shaw Cell

We consider the motion of the flattened bubbles which form when air is injected into a viscous fluid contained in the narrow gap between two flat, parallel plates which make up a conventional Hele-Shaw cell, inclined at an angle x to the horizontal. We present a number of qualitative observations on the formation and interaction of the streams of bubbles that appear when air is injected continuously into the cell. The majority of this paper is then concerned with the shape and velocity of rise of single, isolated bubbles over a wide range of bubble size and cell inclination. We compare these results to theories by Taylor & Saffman (1959), and Tanveer (1986). It appears that the bubble characteristics found by an ad hoc speculation in Taylor & Saffman (1959) and by Tanveer (1986) only agree with the experimental results in the limit α → 0, and for large bubble widths (D). For finite values of α, it is necessary to use the measured bubble shape in order to calculate the rise velocity using the more general Taylor & Saffman (1959) formulation. Deviations from these theories for small D can be explained by considering the effects of the detailed flow close to the bubble surface.

Intermittent Noises Due to Bubbles Sucked Into a Siphon Pipe

2003 ◽  
Author(s):  
Hiroshi Shigefuji ◽  
Osamu Mochizuki
Keyword(s):  
Shear Stress ◽  
Early Stage ◽  
Bubble Formation ◽  
Flow Patterns ◽  
Bubble Surface ◽  
Main Flow ◽  
Large Bubble ◽  
Last Stage ◽  
Small Bubbles

Intermittent noises arising from a siphon pipe attached to a toilet bowl are investigated experimentally. The see-through model of a drained system is used to study the relation between noises and flow patterns near the entrance of the siphon pipe. We observed the different manner of the formation of large bubbles for different values of sucking velocity in the siphon pipe. The overall value of the noise in the sucking period increases with increasing the draining velocity. When the draining velocity is constant, the largest noise is generated at completion of the large bubble attached on the wall. The intermittent noises in the early stage of the period are found to be caused by small bubbles separated from the tail of the large bubble. The small bubbles are torn off because of shear stress of the main flow acting on the bubble surface. Another intermittent noises arising in the last stage is caused by periodic formation of the large bubble near the entrance. The detailed process of the bubble formation in the siphon pipe and the noises are discussed in this paper.

Direct observations of radiation-enhanced transformations in glass

1983 ◽  
Vol 41 ◽  
pp. 354-355
Author(s):  
J. F. DeNatale ◽  
D. G. Howitt
Keyword(s):  
Glass Matrix ◽  
Diffusion Mechanism ◽  
Bubble Formation ◽  
Silicate Glasses ◽  
Phase Decomposition ◽  
Direct Observations ◽  
Thin Foils ◽  
Oxygen Bubble ◽  
Electron Energy Loss ◽  
Kinetics Of

The electron irradiation of silicate glasses containing metal cations produces various types of phase separation and decomposition which includes oxygen bubble formation at intermediate temperatures figure I. The kinetics of bubble formation are too rapid to be accounted for by oxygen diffusion but the behavior is consistent with a cation diffusion mechanism if the amount of oxygen in the bubble is not significantly different from that in the same volume of silicate glass. The formation of oxygen bubbles is often accompanied by precipitation of crystalline phases and/or amorphous phase decomposition in the regions between the bubbles and the detection of differences in oxygen concentration between the bubble and matrix by electron energy loss spectroscopy cannot be discerned (figure 2) even when the bubble occupies the majority of the foil depth.The oxygen bubbles are stable, even in the thin foils, months after irradiation and if van der Waals behavior of the interior gas is assumed an oxygen pressure of about 4000 atmospheres must be sustained for a 100 bubble if the surface tension with the glass matrix is to balance against it at intermediate temperatures.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

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