THE HIGH-TEMPERATURE STABILITY OF THORIA-STRENGTHENED NICKEL-CHROMIUM ALLOYS.
Rept. for Jun 67-Jun 68,
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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Two nickel-base, 20 chromium - 2 thoria alloys, manufactured by different techniques, were studied with regard to their response to high-temperature exposure. Both alloys retained their dislocation substructure after 1-hr annealing treatments up to 1800F. Annealing above this temperature resulted in a decrease in room temperature hardness of one of the alloys, while the other retained its original hardness and remained microstructurally stable up to 2400F. The decrease in hardness was associated with a decrease in the dislocation density and an increase in grain size. The thoria particles in the stable alloy had an average diameter of 550 A, as compared to 820 A for the less stable alloy. It appears that the difference in the particle sizes accounts for the difference in the structural stability at elevated temperatures. Author
- Properties of Metals and Alloys