gm* A STUDY OF THE CRYSTALLINE TRANSFORMATION
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چکیده
A study was made of the high-temperature phase change that occurs in LiAl50s. The reaction has been reported to be either an order-disorder transformation or a reconstructive polymorphic inversion. Kinetics of the phase change with respect to compositional, temperature, and time variables were studied. The spinel structure was found to exist over wide compositional ranges in both lithia-rich and lithia-poor regions. The degree of the defectiveness of the structures affected the transformation rates. The transformation process is diffusion controlled and required a small activation energy. Insufficient evidence was obtained to resolve the question of the type of change that occurs. This technical documentary report has been reviewed and is approved. W. G. RAMKE Chief, Ceramics and Graphite Branch Metals and Ceramics Division AF Materials Laboratory
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