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2 edition of Tensile creep behavior of polycrystalline alumina fibers found in the catalog.

Tensile creep behavior of polycrystalline alumina fibers

H.M Yun

Tensile creep behavior of polycrystalline alumina fibers

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Published .
Written in English


Edition Notes

StatementH.M. Yun et al.
SeriesNASA-TM-106269, N9330938
ID Numbers
Open LibraryOL19299680M

This research effort investigates creep behavior of N/LaPO 4 /Al 2 O 3 composite consisting of a porous alumina matrix reinforced with Nextel fibers coated with monazite in a symmetric cross-ply (0°/90°/0°/90°) s orientation. Tensile creep was examined at temperatures in the °C range for creep stresses ranging from 40 to Cited by: 1. Temperature dependence. The temperature range in which creep deformation may occur differs in various materials. Lead can creep at room temperature and tungsten requires a temperature in the thousands of degrees before creep deformation can occur, while ice will creep at temperatures near 0 °C (32 °F). As a general guideline, the effects of creep deformation . @article{osti_, title = {Mechanical response of ceramics to creep loading}, author = {Blumenthal, W R}, abstractNote = {The mechanical response of small, semi-elliptical, identification-induced surface cracks in fine-grain alumina was studied. The deformation behavior of the crack tip region was monitored using crack opening and surface displacements. @article{osti_, title = {Cracks in materials with hyperbolic-sine-law creep behavior}, author = {Bassani, J L}, abstractNote = {At high stress levels the creep strain rate for many materials varies as the exponential of stress while at low stress levels it varies as stress to some power. An analysis is presented for a stationary crack under antiplane shear or Mode III .

The tensile creep properties of an aluminum- 12 atom% ( wt%) lithium alloy were measured in the temperature range of l50 to deg C and at stresses of , , and psi. The second-stage creep rate of the alloy had an activation energy of 3l.5 kilocalories per mole and varied with stress raised to the power.


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Tensile creep behavior of polycrystalline alumina fibers by H.M Yun Download PDF EPUB FB2

However, in terms of creep behavior, fine diameter polycrystalline alumina fibers (Fiber FP and PRD ) with grain sizes of _ nm have recently been shown to possess low tensile creep strengths of only Tensile creep behavior of polycrystalline alumina fibers book MPa at °C for percent creep strain in 5 hr (ref.

Tensile creep studies were conducted on polycrystalline Nextel and Fiber FP alumina fibers with grain sizes of and nm, respectively. Test conditions were Tensile creep behavior of polycrystalline alumina fibers book from to C and stresses from 60 to MPa.

For both fibers, only a small primary creep portion occurred followed by steady-state : J. Goldsby and H. Yun. Prior work on the polycrystalline alumina fiber Nextel demonstrated Tensile creep behavior of polycrystalline alumina fibers book little grain growth occurred at temperatures up to °C and times of 10 h 2, 3.

However, the same studies showed that, under no-load conditions, the fiber's tensile strength degrades due to the thermally activated growth of critical by: Tensile creep and creep rupture behaviors of alumina/17 vol% silicon carbide nanocomposite and monolithic alumina Were investigated at ° to °C and at 50 to MPa.

On the other hand, the phase transformations caused by the thermal exposures improved the thermal stability of the fibers. As a consequence, the treated fibers were more resistant to creep, i.e., the creep rates decreased.

In summary, this work presents a more detailed analysis on the long-term behavior of oxide fibers at high : Renato Saint Martin Almeida. Polycrystalline yttrium–aluminum garnet, Y 3 Al 5 O 12 (YAG) fiber and α-alumina and YAG matrix composite fiber were prepared by the sol–gel method.

α-Alumina and YAG matrix composite fiber with fine and homogeneous microstructure could be successfully fabricated by interpenetrating YAG in alumina matrix and adding α-alumina of seed particles to by: The solid line is drawn assuming that the a-SiC fiber data point represents the ultimate in creep behavior and that grain size d can be introduced into the semi-empirical eqn (11) by the relation: A, =A1/do.4 -A,/d The choice of an inverse ddependence with p = 0~4 is based on the average p values observed for all the SiC fibers and the fact Cited by: The creep rate decreased significantly by post-fabrication thermal treatments that remove boron from the bulk of these fibers.

Conclusions. Polycrystalline SiC fibers were heat treated at elevated temperatures for 1 h in an Ar atmosphere. The creep resistance of SiC fibers evaluated by BSR method could be improved by heat by: However, the successful synthesis of high strength, fine‐grained YAG fibers has been Tensile creep behavior of polycrystalline alumina fibers book.

In this work, two‐phase YAG‐alumina fibers were synthesized with uniform, fine grain size and high strength. The tensile creep of YAG‐alumina fibers was measured and compared with commercial oxide fibers and single‐phase YAG by: Part of the Materials Technology Series Tensile creep behavior of polycrystalline alumina fibers book series (MTEC, volume 6) Synthesis of polycrystalline alumina fiber with aluminium chelate precursor, J.

Mater. Sci., 26, – (). Tensile creep rupture behavior of alumina based poly-crystalline oxide fibers, Ceram. Eng. Sci. Proc, 13[], – (). Cited by: 3. A tensile creep curve for polycrystalline alumina, with a primary, a secondary, and a tertiary stage is shown in Fig.

2 (Davies and Sinha Ray ). Figure 2. Tensile creep curve for polycrystalline alumina at °C and 40 MPa, showing the three stages of creep deformation: primary (I), secondary (II), and tertiary (III) (after Davies and. The creep behavior of Hi-Nicalon, Hi-Nicalon S, and Tyranno SA3 fibers is investigated at temperatures up to °C.

Tensile tests were carried out on a high-capability fiber. Tensile creep studies were conducted on polycrystalline Nextel and Fiber FP alumina fibers with grain sizes of and nm, respectively. Test conditions were temperatures from.

The tensile creep behavior of an oxide–oxide continuous fiber ceramic composite (CFCC) with ±45° fiber orientation was investigated at °C in laboratory air, in steam and in argon. Abstract: The tensile creep was investigated on a polycrystalline graphite material.A specimen before and after creep was analyzed by RAM ANOR U Raman Spectrum,and the varia- tion of pores on longitudinal profile by SEM results indicate that for a polycrystalline material creep does not take place obviously at ℃ and MPa ini- tial creep.

Get this from a library. Tensile creep behavior of polycrystalline alumina fibers. [Hee Mann Yun; Jon C Goldsby; United States. National Aeronautics and Space Administration.]. Tressler's research works with 2, citations and 1, reads, including: Tensile Creep Rupture Behavior of Alumina‐Based Polycrystalline Oxide Fibers.

The high temperature tensile strength and creep properties of Nextel were measured in the temperature range °C — °C. The creep rate for the Nextel fibers was three orders of magnitude less than single phase polycrystalline alumina fibers such as Nexteland 85% of room tensile strength was retained at ° by: The present work is a report of an experimental study of the tensile creep of a polycrystalline alumina and a SiC whisker reinforced alumina composite.

The focus of the work was on the composite since, as far as the authors are aware, no studies of the tensile creep of this type of material had been reported by: 1. The creep behavior of the matrix was described by an exponential law with elastic behavior of fibers.

Predicting the creep behavior of the short fiber composite “Silicon Carbide/Aluminum ” using high order functions analytically was the novelty of the : Vahid Monfared. The creep behavior of the fibers was assessed by the bend stress relaxation method at various applied strains at °C and °C.

The fibers tested include developmental-grade fibers with different residual silicon amounts (~0%, 2% to 3%, and 5% to 6%) fabricated by laser chemical vapor deposition at Free Form Fibers. The high-temperature creep deformation behavior of commercial polycrystalline-alumina-based libers can be modified by anneahng.

This may offer the opportunity to improve high-temperature creep resistance of composites without affecting their stress-rupture behavior. For multiple- and transition-phased fibers such as Altex, annealing. observed during creep deformation of polycrystalline alumina [2].

The development of a tow-based oxide/oxide ceramic matrix composite (CMC) fiber offers a possible approach for improving the creep response of tow-fibers. In this study, a partially sintered (porous) alumina matrix is incorporated into an alumina tow-fiber, resulting in the File Size: 1MB.

FABRICATION OF POLYCRYSTALLINE YAG/ALUMINA COMPOSITE FIBERS AND YAG FIBER Atsuya TOWATA 1, Hae Jin HWANG, Masaki YASUOKA, Mutsuo SANDO and Koichi NIIHARA 2 1 National Industrial Research Institute of Nagoya, Hirate-cho, Kita-ku, Nagoya, Japan 2 The Institute of Scientific and Industrial Research, Osaka University, File Size: KB.

Fine grained polycrystalline alumina has been deformed in creep at high temperatures, to examine the evolution of cavities at grain boundaries. Cavities with equilibrium and crack-like morphologies have been observed, distributed non-uniformly throughout the by: 5.

The objective of this paper is to compare and analyze bend stress relaxation and tensile creep data for a-SiC fibers produced by the Carborundum Co. (Niagara Falls, NY).

This fiber is of current technical interest and is similar in composition to bulk or-SiC which has been studied under compressive creep conditions (Lane et a1., Nixon and File Size: KB. The creep behavior described above for CVD SiC fibers is very similar to that observed for polycrystalline aluminum wires in the classic creep studies File Size: 1MB.

The creep resistance and strength of polycrystalline ceramics can be improved by the addition of hard se-cond-phase particles and the second-phase particles may affect ceramic grain growth, microstructure, and creep rate by solute drag and grain boundary pinning [6, 7]. For example, when alumina fibers were prepared byAuthor: Xiaoling Ma.

The physical characteristics, fabrication methods, and key microstructural features of all ceramic fibers, both oxides and non-oxides, are tabulated in Table The characteristics of fibers that are commercially available are summarized in Tableincluding maximum use temperature, current uses, and current c oxide fibers (often referred to as oxide fibers) are.

J.R. Porter, W. Blumenthal and A.G. Evans () “Creep Fracture in Ceramic Polycrystals - I. Creep Cavitation Effects in Polycrystalline Alumina,” Acta Cited by:   Optical and Mechanical Behavior of Woven Fabric Al 2 O 3 Fiber‐Reinforced MgAl 2 O 4 Matrix All‐Oxide Optomechanical Composites.

creep behavior of oxide fibers expected to be useful in high-temperature applications. Continuous fiber reinforced composite materials possess numerous structural advantages over their monolithic counterparts; however, the role of the fiber on these.

Tensile creep experiments were carried on AZ91D magnesium alloy and aluminum silicate short fiber-reinforced AZ91D magnesium matrix composite. The creep threshold stress of AZ91D composite depends on the Al atoms solute atmosphere, the bearing and transferring force of short by: 1.

Annealing effects on creep and rupture of polycrystalline alumina-based fibers (OCoLC) Microfiche version: Annealing effects on creep and rupture of polycrystalline alumina-based fibers (OCoLC) Material Type: Document, Government publication, National government publication, Internet resource: Document Type:.

COVID Resources. Reliable information about the coronavirus (COVID) is available from the World Health Organization (current situation, international travel).Numerous and frequently-updated resource results are available from this ’s WebJunction has pulled together information and resources to assist library staff as they consider how to handle.

Annealing effects on creep and rupture of polycrystalline alumina-based fibers (OCoLC) Online version: Goldsby, Jon C. Annealing effects on creep and rupture of polycrystalline alumina-based fibers (OCoLC) Material Type: Government publication, National government publication, Internet resource: Document Type: Book.

Fracture behavior under multiaxial stress state of polycrystalline alumina was studied from the view point of an artificial crack propagation and fracture from a natural flaw.

The former was studied by mixed-mode fracture toughness tests; asymmetric four-point bending and diametral compression techniques were carried out using precracked and notched : Masayuki Tsukada, Eiichi Sato, Kazuhiko Kuribayashi.

Ceramic fibers consisting of mullite and alumina mixtures (e.g., Nextel fibers) have demonstrated creep strengths considerably greater than those observed in single-phase alumina or mullite fibers.

In general, two-phase mixtures exhibit less grain growth than single-phase materials and tend to be more microstructurally stable (French et al. The steady‐state creep behavior of polycrystalline aluminum oxide from 97 to % dense has been examined at temperatures from ° to °C over a range of stresses from to psi under four‐point transverse bending.

Grain size is shown to have an important effect on the deformation behavior. Stress‐strain rate dependence for the fine‐grained aluminum oxide (3.

Understanding the thermomechanical behavior (creep and stress relaxation) of ceramic fibers is of both practical and basic interest. On the practical level, ceramic fibers are the reinforcement for ceramic matrix composites which are being developed for use in high temperature applications.

This volume reviews and updates the creep behavior of advanced materials, including ceramic and metal-matrix composites, pdf materials, nanostructured materials, advanced intermetallics, and advanced dispersion strengthened materials. This collection from the TMS Annual Meeting & Exhibition also covers the influence of microstructure on various aspects of creep .Polycrystalline alumina fibers were prepared by sol-gel method.

The influence of download pdf rate on average tensile strength of fibers as well as the influence of calcining temperature on average tensile strength of fibers, crystal phases form, specific surface area of fibers were studied.

The results show that when the heating rate (below °C) is 4°C/min,the average tensile strength Cited by: 1.TENSILE STRESS-RUPTURE AND CREEP CHARACTERISTICS Ebook TWO GLASS-FABRIC-BASE PLASTIC LAMINATES No. June INFORMAT!fl9 RFV1EWED' AND REAFFiRMED This Report is One of a Series Issued in Cooperation with the ANC PANEL ON PLASTICS FOR AIRCRAFT of the Departments of the AIR FORCE, NAVY, AND .