scholarly journals SHP solution of effect of elevated temperature on tunnel lining

2008 ◽  
Author(s):  
P. Procházka ◽  
S. Peskova
Keyword(s):  
Elevated Temperature ◽  
Tunnel Lining

Evidence for a shear mechanism for the precipitation of γ-zirconium hydride in zirconium

1978 ◽  
Vol 36 (1) ◽  
pp. 658-659
Author(s):  
G.J.C. Carpenter
Keyword(s):  
Elevated Temperature ◽  
Strain Field ◽  
Zirconium Hydride ◽  
Zirconium Atom ◽  
Atom Diffusion ◽  
Solvus Temperature ◽  
Hexagonal Close Packed ◽  
Partial Dislocations ◽  
The Face

In zirconium-hydrogen alloys, rapid cooling from an elevated temperature causes precipitation of the face-centred tetragonal (fct) phase, γZrH, in the form of needles, parallel to the close-packed <1120>zr directions (1). With low hydrogen concentrations, the hydride solvus is sufficiently low that zirconium atom diffusion cannot occur. For example, with 6 μg/g hydrogen, the solvus temperature is approximately 370 K (2), at which only the hydrogen diffuses readily. Shears are therefore necessary to produce the crystallographic transformation from hexagonal close-packed (hep) zirconium to fct hydride.The simplest mechanism for the transformation is the passage of Shockley partial dislocations having Burgers vectors (b) of the type 1/3<0110> on every second (0001)Zr plane. If the partial dislocations are in the form of loops with the same b, the crosssection of a hydride precipitate will be as shown in fig.1. A consequence of this type of transformation is that a cumulative shear, S, is produced that leads to a strain field in the surrounding zirconium matrix, as illustrated in fig.2a.

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.

Stress state analysis of two-way tunnel lining at different stages of soil defrostation

2019 ◽  
Vol 10 ◽  
pp. 160-171
Author(s):  
M.S. Pleshko ◽  
◽  
M.V. Pleshko ◽  
I.V. Voynov ◽  
A.V. Kostyukhov ◽  
...  
Keyword(s):  
Stress State ◽  
Tunnel Lining ◽  
State Analysis

Pulse Velocity Behaviour of glass fibre self compacting concrete at Elevated Temperature

2010 ◽  
Vol 6 (1) ◽  
pp. 40-43
Author(s):  
T. Seshadri Sekhar ◽  
◽  
P. Sravana ◽  
P. Srinivasa Rao ◽  
◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Glass Fibre ◽  
Pulse Velocity ◽  
Self Compacting Concrete

A Finite Element (FE) simulation of naked solid steel beam at elevated temperature

2018 ◽  
Vol 10 (9) ◽  
Author(s):  
Fariz Aswan Ahmad Zakwan ◽  
◽  
Renga Rao Krishnamoorthy ◽  
Azmi Ibrahim ◽  
Ruqayyah Ismail ◽  
...  
Keyword(s):  
Finite Element ◽  
Elevated Temperature ◽  
Fe Simulation ◽  
Steel Beam
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