Accession Number : ADA329853

Title :   High Temperature Heterogeneous Materials

Descriptive Note : Final rept. 15 Jan 90-31 Aug 93

Corporate Author : NORTHWESTERN UNIV EVANSTON IL CENTER FOR QUALITY ENGINEERING AND FAILURE PREV ENTION

Personal Author(s) : Keer, Leon M. ; Faber, K. T. ; Moran, B. ; Weertman, J.

PDF Url : ADA329853

Report Date : 22 JUL 1994

Pagination or Media Count : 26

Abstract : Experimental and supporting analytical methodologies for the determination and assessment of the integrity of interfaces in composite materials at both room and high temperatures are presented. Experimental test techniques developed in the program are described and supporting analytical methods to assist in the determination of interface fracture toughness from experimental measurements are presented. The test techniques consist of the tensile test on a thin coated fiber and four point bend of a bimaterial bar and were chosen on the basis of their suitability for use at high temperatures. An experimental study of crack tip shielding/antishielding by impurities in alpha-silicon carbide is described. This investigation required the application of stress during high temperature (1873 K) anneals. A novel stress fixture, based on thermal expansion mismatch, was designed, constructed and utilized to achieve this in-situ stressing of the crack specimens at high temperatures.

Descriptors :   *CRACKING(FRACTURING), *FIBER REINFORCED COMPOSITES, COMPUTER PROGRAMS, METHODOLOGY, TENSILE STRENGTH, FINITE ELEMENT ANALYSIS, THERMAL EXPANSION, SILICON CARBIDES, BINARY ALLOYS.

Subject Categories : Laminates and Composite Materials
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE