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Polycrystalline beryllium normally fails under ballistic impact at values of 0.3 to 0.7 foot-pounds when the specimen is 0.100 inch thick. This failure is accompanied by fast propagation of cracks resulting in actual shattering of the specimen. While the actual impact energy required to produce a crack was not substantially improved in the course of this work, several procedures were identified which materially limited the propagation of the cracks and delayed the shattering phenomenon. The ballistic impact resistance of 0.100 inch thick single crystal specimens of the major orientations was tested and found to be slightly better than the performance of the polycrystalline metal. The most favorable orientation was impact on a plane inclined at about 45 deg. to the basal plane. (Author)

The study shows that the A1FeBe4 reaction to be reversible, the dissolution of the phase being accompanied by an increase in free aluminum, with reasonable evidence for iron being in solid solution. Both room- and elevated-temperature strengths are strongly dependent on the reaction, strength increasing with excess iron, i.e., iron not combined as A1FeBe4. Room-temperature ductility showed no consistent dependence on the phase behavior; however, elevated-temperature ductility varied considerably with iron and aluminum contents. In general, optimum ductilities correspond to iron/aluminum weight ratios of two or greater and/or low aluminum contents. Aging generally lowers strength properties at all temperatures, and has little effect on room-temperature ductility. On the other hand, aging was shown to increase elevated-temperature ductility in all cases tested. (Author), Prepared for presentation at the International Conference on Beryllijm Metallurgy and Technology Philadelphia, Pa., Oct 64.