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Title: High-temperature phase equilibria in the Al-rich corner of the Al-Ti-C system

A thermodynamic analysis of the Al-rich corner in the ternary Al-Ti-C diagram, providing phase relations and regions of phase stability, is presented. An invariant four-phase equilibrium between Al, Al{sub 4}C{sub 3}, Al{sub 3}Ti, and TiC{sub x} takes place at 0.53 at. pct Ti, 7.10{sup {minus}6} at. pct C, and TiC{sub 0.883} at 966 K. The carbon content of the TiC{sub x} phase, which extends from x = 0.48 to 0.98, exerts a significant effect on phase relationships in this ternary system. In particular, it is shown that stoichiometric TiC is not stable in the presence of liquid Al. For example, at 1,300 K, a two-phase equilibrium between Al{sub L} and TiC{sub x} exists only in the 0.91 < x < 0.82 range. Thus, the interaction of Al{sub L} with stoichiometric TiC leads to the formation of the Al{sub 4}C{sub 3} aluminum carbide phase, whereas for x < 0.82, only the intermetallic compound Al{sub 3}Ti can form at this temperature. The results of this analysis were confirmed by X-ray diffraction (XRD) measurements of relevant composites.
Authors:
; ; ; ;  [1]
  1. Ben-Gurion Univ. of the Negev, Beer-Sheva (Israel). Dept. of Materials Engineering
Publication Date:
OSTI Identifier:
616505
Resource Type:
Journal Article
Resource Relation:
Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science; Journal Volume: 29; Journal Issue: 4; Other Information: PBD: Apr 1998
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; TITANIUM CARBIDES; PHASE STUDIES; THERMODYNAMICS; COMPOSITE MATERIALS; CARBON FIBERS; MICROSTRUCTURE