Accession Number : ADA326796

Title :   Intermetallic Matrix Composites via in-situ Displacement Reactions.

Descriptive Note : Final rept. 1 Jul 91-30 Jun 95,

Corporate Author : FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Kaufman, Michael

PDF Url : ADA326796

Report Date : JUN 1997

Pagination or Media Count : 11

Abstract : Among the obstacles encountered in the development of intermetallic matrix composites are (1) the thermodynamic and mechanical incompatibility between the matrix and reinforcement phases and (2) the matrix reinforcement interfacial properties which are not ideal from the standpoint of achieving optimum properties in the composite as a whole. In the past, the first of these problems has been addressed by coating the reinforcements with some sort of barrier or compliant layer before their introduction into the matrix. The various coating methods investigated (sol-gel, CVD, PVD) tend to be expensive, time consuming and unreliable with respect to producing sound coatings. This research program was initially concentrated on identifying more cost effective and reliable schemes for developing the requisite coatings. The basic approach is to identify simple processing schemes whereby a beneficial reaction product (or products) is produced in-situ at the interfaces between the matrix and reinforcement during consolidation or subsequent heat treatment. As the research evolved, greater focus was placed on the need to achieve a better understanding of microstructural evolution during in-situ displacement reactions and on the correlation between the evolved microstructures and the mechanical properties. In the case of silicide based IMC's, there was a clear need to determine the influence of discrete silica particles, incorporated during the consolidation of powder samples, on the mechanical properties and on both grain size and shape.

Descriptors :   *MICROSTRUCTURE, *METAL MATRIX COMPOSITES, *DISPLACEMENT REACTIONS, MECHANICAL PROPERTIES, INTERFACES, SILICON DIOXIDE, THERMODYNAMICS, POWDERS, ELASTIC PROPERTIES, GRAIN SIZE, HEAT TREATMENT, SILICIDES, MOLYBDENUM ALLOYS, INTERMETALLIC COMPOUNDS, REINFORCEMENT(STRUCTURES), BARRIER COATINGS.

Subject Categories : Laminates and Composite Materials
      Mfg & Industrial Eng & Control of Product Sys
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE