An investigation of iron intermetallics, silicon particles and strengthening precipitates on the microstructures and mechanical properties in B319.0 alloys has been performed. Distinct morphologies were discerned between Be-containing and Be-free alloys at various solution temperatures. Solution treatment was carried out in the temperature range 480 degrees C-530 degrees C for 8 h. Dissolution of the iron intermetallics takes place at temperatures close to 510 degrees C. through fragmentation of the phases. The dissolution of iron intermetallics is accelerated with increasing solution temperature. The addition of Be to the alloy will raise the Al-Al-2 Cu eutectic melting temperature to 522 degrees C compared with 515 degrees C for Be-free alloys. The Be-free alloys show larger amounts of iron intermetallics than the Be-containing alloys. The addition of Be can change the platelet-like shape of iron intermetallic phases to a comparatively harmless Chinese-script shape. Also, the amount of iron-bearing phases and silicon particles are lower and silicon particles are smaller and more spherical in the Be-containing alloys. Small amounts of Be in B319.0 alloys can also increase the precipitation kinetics of strengthening precipitates. Tensile properties could be improved with optimal solution treatment and the addition of Be. (C) 1998 Elsevier Science S.A. All rights reserved.