Thermal Deformation of Woven Composites at High Temperatures

2022 ◽  
Author(s):  
M. K. Kucher ◽  
O. O. Chyzhyk
Keyword(s):  
High Temperatures ◽  
Thermal Deformation ◽  
Woven Composites

Thermal deformation and strength of composite materials at high temperatures

1987 ◽  
Vol 22 (5) ◽  
pp. 545-550
Author(s):  
G. N. Tret'yachenko ◽  
L. I. Gracheva
Keyword(s):  
Composite Materials ◽  
High Temperatures ◽  
Thermal Deformation

Prediction of Lifetime in Static Fatigue at High Temperatures for Ceramic Matrix Composites

2010 ◽  
Vol 112 ◽  
pp. 129-140 ◽  
Author(s):  
O. Loseille ◽  
Jacques Lamon
Keyword(s):  
Crack Growth ◽  
High Temperatures ◽  
Slow Crack Growth ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Woven Composites ◽  
Static Fatigue ◽  
Matrix Composites ◽  
Random Load ◽  
Delayed Failure

Previous works have shown that ceramic matrix composites are sensitive to delayed failure during fatigue in oxidizing environments. The phenomenon of slow crack growth has been deeply investigated on single fibers and multifilament tows in previous papers. The present paper proposes a multiscale model of failure driven by slow crack growth in fibers, for 2D woven composites under a constant load. The model is based on the delayed failure of longitudinal tows. Additional phenomena involved in the failure of tows have been identified using fractographic examination of 2D woven SiC/SiC composite testspecimens after fatigue tests at high temperatures. Stochastic features including random load sharing, fiber overloading, fiber characteristics and fiber arrangement within the tows have been introduced using appropriate density functions. Rupture time predictions are compared to experimental data.

In situ REM imaging of surface processes on ceramic bulk crystals from 300 to 1670 K in a conventional TEM

1991 ◽  
Vol 49 ◽  
pp. 660-661
Author(s):  
Z. L. Wang ◽  
J. Bentley
Keyword(s):  
High Temperatures ◽  
Image Resolution ◽  
Atomic Processes ◽  
Crystal Surfaces ◽  
Beam Radiation ◽  
Surface Areas ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Gas Reactions

Studying the behavior of surfaces at high temperatures is of great importance for understanding the properties of ceramics and associated surface-gas reactions. Atomic processes occurring on bulk crystal surfaces at high temperatures can be recorded by reflection electron microscopy (REM) in a conventional transmission electron microscope (TEM) with relatively high resolution, because REM is especially sensitive to atomic-height steps.Improved REM image resolution with a FEG: Cleaved surfaces of a-alumina (012) exhibit atomic flatness with steps of height about 5 Å, determined by reference to a screw (or near screw) dislocation with a presumed Burgers vector of b = (1/3)<012> (see Fig. 1). Steps of heights less than about 0.8 Å can be clearly resolved only with a field emission gun (FEG) (Fig. 2). The small steps are formed by the surface oscillating between the closely packed O and Al stacking layers. The bands of dark contrast (Fig. 2b) are the result of beam radiation damage to surface areas initially terminated with O ions.

Experimental study of thermal deformation of honeycombed PCM cooled mirror in resonator

2002 ◽  
Vol 12 (4) ◽  
pp. 271-280 ◽  
Author(s):  
Feng Sun ◽  
Wenfeng Yu ◽  
Zuhai Cheng ◽  
Yaoning Zhang
Keyword(s):  
Experimental Study ◽  
Thermal Deformation

Measuring the electric resistance of metals and alloys at high temperatures by a hardware-and-software system

2018 ◽  
pp. 60-64 ◽  
Author(s):  
M. Yu. Chernoskutov ◽  
A. D. Ivliev ◽  
V. V. Meshkov ◽  
A. O. Samoilov ◽  
A. S. Sosnin
Keyword(s):  
High Temperatures ◽  
Metals And Alloys ◽  
Software System ◽  
Electric Resistance ◽  
Hardware And Software System

High Temperature n- and p-type Doped Microcrystalline Silicon Layers Grown by VHF PECVD Layer-by-Layer Deposition

2003 ◽  
Vol 762 ◽  
Author(s):  
A. Gordijn ◽  
J.K. Rath ◽  
R.E.I. Schropp
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
High Temperatures ◽  
Continuous Wave ◽  
Hydrogen Plasma ◽  
Silicon Layer ◽  
Dark Conductivity ◽  
High Deposition Rate ◽  
Layer By Layer ◽  
Microcrystalline Silicon

AbstractDue to the high temperatures used for high deposition rate microcrystalline (μc-Si:H) and polycrystalline silicon, there is a need for compact and temperature-stable doped layers. In this study we report on films grown by the layer-by-layer method (LbL) using VHF PECVD. Growth of an amorphous silicon layer is alternated by a hydrogen plasma treatment. In LbL, the surface reactions are separated time-wise from the nucleation in the bulk. We observed that it is possible to incorporate dopant atoms in the layer, without disturbing the nucleation. Even at high substrate temperatures (up to 400°C) doped layers can be made microcrystalline. At these temperatures, in the continuous wave case, crystallinity is hindered, which is generally attributed to the out-diffusion of hydrogen from the surface and the presence of impurities (dopants).We observe that the parameter window for the treatment time for p-layers is smaller compared to n-layers. Moreover we observe that for high temperatures, the nucleation of p-layers is more adversely affected than for n-layers. Thin, doped layers have been structurally, optically and electrically characterized. The best n-layer made at 400°C, with a thickness of only 31 nm, had an activation energy of 0.056 eV and a dark conductivity of 2.7 S/cm, while the best p-layer made at 350°C, with a thickness of 29 nm, had an activation energy of 0.11 V and a dark conductivity of 0.1 S/cm. The suitability of these high temperature n-layers has been demonstrated in an n-i-p microcrystalline silicon solar cell with an unoptimized μc-Si:H i-layer deposited at 250°C and without buffer. The Voc of the cell is 0.48 V and the fill factor is 70 %.

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