Accession Number : ADA334772

Title :   A Study in the Interfacial Stability of Ti/Al2O3, Ti3Al/Al2O3 and TiAl/Al2O3 Composite Materials

Descriptive Note : Final rept.

Corporate Author : AIR FORCE RESEARCH LAB BOLLING AFB DC

Personal Author(s) : DeKock, Joel A.

PDF Url : ADA334772

Report Date : 1995

Pagination or Media Count : 172

Abstract : This thesis is a study of the interfacial stability of the Ti-Base metal matrix composites Ti/Al2O3, Ti3Al/Al2O3 and TiAl/Al2O3. Interfacial stability is discussed in view of the importance of thermodynamics and kinetics as the primary considerations which govern the type of stability observed. From a thermodynamics approach, the application of phase equilibrium diagrams is essential in the design of composite systems. A classification system, with reference to phase equilibrium, is used to describe the type of interfacial stability observed for the composites studied. In addition, electron-probe microanalysis, atom-probe field ion microscopy and X-ray diffraction results are used to establish Ti-Al-O phase relations for the temperature range 900-to-1250 deg C. The kinetics of interfacial stability is discussed with particular attention given to the kinetic considerations; diffusion path, phase formation sequence, steady-state layer growth and interface morphology. Kinetic results in the form of parabolic growth constants and calculated interdiffusion coefficients are presented.

Descriptors :   *STABILITY, *INTERFACES, *ALUMINUM OXIDES, *TITANIUM ALUMINIDE, *TITANIUM COMPOUNDS, STEADY STATE, LAYERS, THERMODYNAMICS, COMPOSITE MATERIALS, GROWTH(GENERAL), MORPHOLOGY, X RAY DIFFRACTION, THESES, METAL MATRIX COMPOSITES, CRACK PROPAGATION, CLASSIFICATION, DIFFUSION, KINETICS, PHASE DIAGRAMS, MICROANALYSIS, ELECTRON PROBES.

Subject Categories : Laminates and Composite Materials
      Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE