Beryllium Improvement Program.
Final rept. 1 May 70-19 Feb 73,
LOCKHEED MISSILES AND SPACE CO INC SUNNYVALE CALIF
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A program was conducted to investigate and to define the material orprocess variables which must be controlled in order to optimize the short time compression creep behavior of hot-pressed beryllium at 1500 to 1800F. The program goal was to develop a commercially feasible material with improved creep resistance, but without significant sacrifice of other mechanical properties. Materials were studied and characterized by compression creep tests, room and elevated temperature 300-500F tensile tests, medium strain rate tensile tests, chemistry, grain size, microstructural constituents and salient process parameters. It is shown that maintaining low impurity levels, particularly of the elements, Mg, Si, and Al and developing a fine, uniform distribution of BeO in fine-grained beryllium led to improved creep resistance at 1800F. This improvement was one-to-three orders-of-magnitude over typical commercial material, thereby meeting and exceeding the proposed program goal of one-order-of-magnitude improvement. In addition other mechanical properties were either relatively unchanged or improved. A material specification outline was established to serve as a guide for production of creep resistance, commercial beryllium with properties that will meet the minimum program goals. Author
- Properties of Metals and Alloys