Accession Number : ADA329561

Title :   Melt Drawing/Coating of Oxide Fibers for Composite Materials Applications.

Descriptive Note : Final rept. Oct 95-Feb 96,

Corporate Author : CONTAINERLESS RESEARCH INC EVANSTON IL

Personal Author(s) : Weber, J. K. ; Felten, J. J. ; Nordine, P. C. ; Kriven, W. M.

PDF Url : ADA329561

Report Date : 21 MAR 1996

Pagination or Media Count : 43

Abstract : Undercooled oxide melts achieved a melt viscosity sufficient to draw mullite fibers whose chemical, microstructural, and mechanical properties were measured. Tensile strengths were 5.61 +/- 0.71 GPa (810 +/- 100 KSI) for as-drawn, amorphous fibers of 10-40 micron diameter and up to 1.0 GPa after crystallization by annealing in air. Melt drawing of YAG fibers was also demonstrated. Fiber coatings were formed by pulsed excimer laser ablation. Push-out tests on coated fibers imbedded in a ceramic matrix gave small values of the debonding shear strength, tau d ^ 25 MPa, for fibers coated with 2 MgO-SiO2 (enstatite) which provided an interphase-weakening effect. Somewhat larger values of tau d were obtained for LaPO4 coated fibers which provide an interface-weakening effect. Mullite fibers with YPO4 coatings exhibited chemical and dimensional stability during a 2 hour anneal in an aluminum oxide matrix at 1500 deg C. The fiber-pulling process has potential for scale-up to produce high quality oxide fibers at less than $100 per pound.

Descriptors :   *FIBERS, YTTRIUM ALUMINUM GARNET, ANNEALING, TENSILE STRENGTH, CERAMIC MATRIX COMPOSITES, COATINGS, EXCIMERS, SHEAR STRENGTH.

Subject Categories : Test Facilities, Equipment and Methods
      Mechanics
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE