EFFECTS OF PRESTRAINING UNDER HYDROSTATIC PRESSURE ON THE MECHANICAL BEHAVIOR OF POLYCRYSTALLINE BERYLLIUM.
Final rept. 1 Jun 66-31 Jan 67,
FRANKLIN INST RESEARCH LABS PHILADELPHIA PA
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The effects of hydrostatic pressure up to 400 ksi and at 25 C to 300 C on the mechanical properties of three forms of beryllium hot-pressed block, extruded rod and cross-rolled sheet were investigated. Three effects of pressure were studied mechanical behavior under pressure, the effect of pressure cycling on the subsequent atmospheric pressure mechanical properties and the effects of prestraining under hydrostatic pressure on the subsequent atmospheric pressure mechanical properties. Pressure cycling did not produce a significant improvement in the tensile ductility of the hot-pressed and the extruded materials it did, however, given an improvement in the tensile and bend ductility of the sheet. With the possible exception of an improvement in the bend ductility of sheet, tensile prestraining under hydrostatic pressure either produced no change in the subsequent atmospheric pressure ductility or there resulted a decrease. The prestraining did, however, give an increase in yield and fracture stresses. The results obtained in the present investigation suggest that the principal effect of pressure is on the fracture stress rather than on the flow stress. Author
- Properties of Metals and Alloys