Investigation of Light Weight, Impact Resistant, Lamellar Composites of Titanium-Clad Beryllium for Air Breathing Engine Compressor Blades

Lamellar composites of beryllium and titanium have been tested by ballistic impact, tensile testing after impact, and impacting while under tensile stress. The titanium cover plates minimize and localize damage to the beryllium core. Use of high strength beryllium sheet to maximize the strength- to-weight ratio of the composite resulted in increased ballistic impact damage. For all types of beryllium utilized, the damage induced by ballistic impact energy levels of 1 ft-lb and greater in specimens while under tensile load, lead to crack propagation throughout the cross-section of the beryllium substrate with a resultant loss in load carrying ability. Therefore future efforts on this composite approach for turbine engine blading is not warranted. The program was aimed at rapid evaluation of composite potential in the one application and materials and techniques were not optimized. Potential in other less demanding areas or armoring was not evaluated.