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Energies of up to 3 kJ g−1 were deposited in thin aluminium foils by means of a pulsed electron beam with a duration of 35 ns. The subsequent expansion of the foils was observed using high-speed photography and compared with that predicted from numerical solutions of the equations of motion. The velocities observed were about double those calculated. The limitations of the expansion equation of state used in the calculations are discussed.The variation of the spall strength of aluminium with temperature was derived from the measured energy deposition thresholds to spall foils of different thicknesses. It was found to fall from 12·5×108 N m−2 (12·5 kbar) at 350°C to about 4×108 N m−2 at 600°C with some evidence for a strength in the solid-liquid phase of a fraction of a kilobar.

Filament tensile strengths and pressure-strain characteristics for a high-modulus, boron-filament-wound/resin composite, pressure vessel were obtained. Five 8-in.-diameter by 13-in.-long boron-filament-wound, metallined pressure vessels were fabricated and burst tested (three at 75 F and two at −320 F) with the following results : 1. The average ultimate boron-filament strength at room temperature was 236,600 psi. The values obtained were highly consistent, varying only 1.9 percent from the average. 2. At −320 F, the boron-filament strength increased about 16 percent to 273,800 psi. 3. Naval Ordnance Laboratory (NOL) rings fabricated from the same boron-filament tape used in the test vessels had an average ultimate filament strength of 309,000 psi at room temperature. The vessels achieved 77 percent of this value. 4. Good correspondence was obtained between the expected and the measured pressure strain characteristics at 75 and −320 F. At the vessel burst points, the strains were about 0.30 to 0.40 percent, roughly one tenth of the strain encountered in glass-filament-wound vessels. 5. The resin content in the boron filament-wound composite ranged from 37 to 47 volume percent. The vessels displayed very low biaxial strains and high strength-to-weight ratios. Such low strains permit strong metal liners (for example, titanium) to work elastically up to the ultimate stress of boron filament. The present strength and potential strength of boron are high enough to ensure that boron-filament-wound, metal-lined vessels will be lighter than competing homogeneous metal tanks for cryogenic service.

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