RECOVERY PROCESSES AND ORDERING IN NI3A1.
WAYNE STATE UNIV DETROIT MICH
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Isothermal changes in long-range order, S, x-ray line shifts due to stacking faults, delta, and x-ray particle size from Fourier analysis of line shapes, D, were measured for filed samples of Ni3A1. Recovery temperatures between 200 degrees C. and 270 degrees C. were investigated. The recovery of all three measured properties appeared to depend upon the mobility of vacancies in this temperature range. The evaporation of vacancies from faulted loops appeared to supply the vacancy flux for ordering and particle size changes. Fault shrinkage was found to cease quite abruptly between 215 degrees C. and 200 degrees C. at 200 degrees C. faulting initially increased, during which ordering did not occur, but after some 20 hours the faulting began to anneal out and somewhat later ordering proceeded. An activation energy of 1.65 eV was found for the ordering reaction this compares with a value of 1.5 eV for Evm in nickel. Author
- Properties of Metals and Alloys
- Electricity and Magnetism
- Solid State Physics