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THE VACUUM HOT-PRESSING OF BERYLLIUM
T.E. Clare, P. Dennis Smith, William Jordan Wright
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Abstract
The optimum conditions for vacuum hot pressing of Pechiney electrolytic beryllium powder have been established and compacts produced with densities exceeding 99 per cent, of theoretical density; these conditions depend markedly on the geometry of the compact and the oxide content of the powders being pressed, Effects of compact geometry, including low densities in long compacts, are associated with loss of pressure through die—wall friction, particularly where the length—to—diameter ratio of the compacts is greater than 0.5 .\nThe presence of 2.3 per cent, beryllium oxide as a surface film on the particles reduced the final density attained to less than 97 per cent, of theoretical when pressing with 1500 lb/in2 at 1080ºC whereas this density could be attained in unoxidised powder with only 800 lb/in2 for similar conditions. The narrow size range of the oxidised powder may also have contributed to this difficulty in pressing.