SUPERLATTICE INTRINSIC STACKING-FAULTS IN GAMMA-'-PRECIPITATES

The material properties of MA 6000 depend largely upon strengthening by L1//2 ordered gamma prime precipitates and to a lesser extent upon solid solution hardening. The microstructure shows that superlattice dislocations coupled together by antiphase boundaries (APB) play a minor role in deformation at 760 degree C and 790 degree C. Yet a few superdislocations inside gamma prime precipitates are found. Measuring the distance between two dislocations is a suitable method to obtain an estimate of the APB energy. The reliability of the estimate is influenced by residual stresses, nevertheless, the antiphase boundary energy on LT AN BR 111 RT AN BR of gamma prime precipitates is calculated to be 144 ( plus or minus 10%) mJ/m**2.