Title page for ETD etd-05012000-11530012


Type of Document Dissertation
Author Marte, Judson Sloan
Author's Email Address marte@crd.ge.com
URN etd-05012000-11530012
Title CODEFORMATION PROCESSING OF MECHANICALLY-DISSIMILAR METAL/INTERMETALLIC COMPOSITES
Degree PhD
Department Materials Science and Engineering
Advisory Committee
Advisor Name Title
Kampe, Stephen L. Committee Chair
Aning, Alexander O. Committee Member
Christodoulou, Leonitus Committee Member
Crowe, C. Robert Committee Member
Reynolds, William T. Jr. Committee Member
Sturges, Robert H. Committee Member
Keywords
  • Reaction Synthesis
  • Powder Metallurgy
  • Extrusion
  • Intermetallic Matrix Composites
  • Metal Matrix Composites
  • Codeformation
Date of Defense 1999-01-12
Availability unrestricted
Abstract
A systematic and scientific approach has been applied to the study of codeformation processing. A series of composites having mechanically-dissimilar phases were developed in which the high temperature flow behavior of the reinforcement material could be varied independent of the matrix. This was accomplished through the use of a series of intermetallic matrix composites (IMCs) as discontinuous reinforcements in an otherwise conventional metal matrix composite.

The IMCs are produced using an in-situ reaction synthesis technique, called the XD™ process. The temperature of the exothermic synthesis reaction, called the adiabatic temperature, has been calculated and shown to increase with increasing volume percentage of TiB2 reinforcement. Further, this temperature has been shown to effect the size and spacing of the TiB2, microstructural features which are often used in discontinuous composite strength models.

Study of the high temperature flow behavior of the components of the metal/IMC composite is critical to the development of an understanding of codeformation. A series of compression tests performed at 1000° to 1200°C and strain-rates of 10-3 and 10-4 sec-1. Peak flow stresses were used to evaluate the influence of material properties and process conditions. These data were incorporated into phenomenologically-based constitutive equations that have been used to predict the flow behavior. It has been determined that plastic deformation of the IMCs occurs readily, and is largely TiB2 independent, at temperatures approaching the melting point of the intermetallic matrices.

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