Isothermal changes in long‐range orderS, x‐ray line shifts due to stacking faults &Dgr;, and x‐ray particle size from Fourier analysis of line shapesDwere measured for filed samples of Ni3Al. Recovery temperatures between 200° and 270°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° and 200°C; at 200°C faulting initially increased, during which ordering did not occur, but after some 20 h 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 forEmvin nickel.