Density and layer thickness as a function of volume percent Mg for monolithic pellets fabricated by hot-pressing the tape cast Mg-Cu powder mixtures.
SEM micrographs of fracture surfaces from monolithic pellets fabricated from tape cast powders: (a) Mg, (b) Mg, (c) Mg, (d) Mg (balance Cu).
Longitudinal sound wave velocity and acoustic impedance as a function of volume percent Cu for monolithic pellets fabricated by hot-pressing the tape cast Mg-Cu powder mixtures. The dotted line shows velocities predicted by the Reuss (constant stress) model, and the solid line shows velocities predicted by the Voigt (constant strain) model.
(a) Impedance profile and layer stacking sequence for an initial graded impactor fabricated from seven compositions of tape cast Mg-Cu powders. (b) SEM micrograph of a polished cross section of the graded impactor in (a).
C-Scan of a graded impactor which also has seven tape compositions, but a slightly different profile than in Fig. 4.
Impedance profile and layer stacking sequence for a graded impactor fabricated from 19 compositions of tape cast Mg-Cu powders.
White light interferometer (Zygo) profile of surface flatness for the impactor profiled in Fig. 6. Top: Mg side. Bottom: Cu side.
Line-outs from Fig. 7 for the impactor profiled in Fig. 6. (a) Mg, (b) Cu, (c) difference between (a) and (b) giving an overall indication of the flatness and parallelism of the impactor.
Particle velocity versus compression time for gas gun experiments using graded impactors with seven (left axis) and 19 (right axis) composition layers to impact 2 mm thickness Al targets. The impact velocities were 1.67 and 1.93 km/s, respectively.
A 1D hydrodynamic simulation of the graded impactor striking an Al target shows how a discretely layered impactor imparts a pressure ramp to the target. The pressure is shown as a function of position relative to the impact plane at 0.0 mm. To the left is the graded impactor and to the right is the Al target. Initially a shock wave propagates from the impact plane to both the left and right (gray line ); then a pressure ramp is created in accord with the impedance profile of the impactor, which propagates into the target. The solid line is at and subsequent traces represent time increments of .
Measured characteristics of several graded impactors fabricated from the tape cast Mg-Cu powder mixtures. Values are expressed as the percentage of that predicted from the stacking sequence and the individual tape characteristics.
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