Hypervelocity penetration of tungsten sinter-alloy rods into aluminum

The penetration of tungsten sinter-alloy rods having length-to-diameter ratios of L/D = 10 and 12.5 into alumina targets was investigated in the velocity range v(p) = 1.25 to 3 km/s. The depth of penetration (DOP) test and the time resolved oberservation using a 600 kV flash X-ray system were applied to assess the protection efficiency of the ceramics. From DOP tests, the residual penetration into a steel backing yields the differential efficiency factor DEF and the mass efficiency factor MEF. DEF increases with v(p); MEF decreases. On the other hand, DEF decreases as ceramic thickness increases; MEF increases and converges to DEF for residual penetration zero. From the time resolved measurements, position and length reduction of the rod during penetration in the ceramics were obtained. The process can be described by Tate's fluid jet model in good approximation. The target resistance parameter R, defined in the modified Bernoulli equation, characterizes the ceramic performance. The average R values are 5.4, 6.1 and 4.8 GPa at impact velocities v(p) = 1.7, 2.5 and 3 km/s, respectively, i.e. there is no strong dependence of R on v(p).