A Study of Interfacial Reactions in Titanium/Sapphire (Al2O3) Composites.
GRUMMAN AEROSPACE CORP BETHPAGE N Y RESEARCH DEPT
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The reactions between sapphire filaments and Ti70A and Ti75A matrices were studied over the temperature range 600 to 1000C for various times. The filament decomposed through diffusion of both aluminum and oxygen into the Ti matrix, resulting in a series of TixAly compounds formed adjacent to the filament with aluminum and oxygen diffusion gradients ahead of the zone. Two rate constants were measured for the reaction zone growth an activation energy of 23 Kcalmole was calculated above 800C and a value of 53 Kcalmole below. It was determined from Microhardness measurements in the matrix that oxygen diffusion was primarily occurring. Unless the embrittling effects of the reaction can be controlled, it appears that Tial2O3 composites will not be a viable system as compared to TiB or tiSiC composites. Author
- Laminates and Composite Materials