Tape Casting Technique for Fabrication of Graded-Density Impactors for Tailored Dynamic Compression

Recently, the use of graded density impactors for dynamic compression experiments has received increasing interest. These gas gun experiments have demonstrated complex loading paths which can last microseconds, and may be capable of bridging the timescales of existing static and dynamic compression experiments. A tape casting technique has been developed for fabrication of the impactors. In the technique, a series of tapes were prepared in the Mg-Cu system with compositions ranging from 100% Mg to 100% Cu. The tapes were characterized for their layer thickness, density, and sound wave velocity. Impactors were fabricated by punching individual layers from the tapes, stacking and laminating them, removing the organic matrix, and hot-pressing the laminated structure. The density profile is determined by the order in which the tapes are stacked in the laminate and is therefore highly flexible. The resultant thickness and average density of the impactors is consistent with the data for the individual layers. Impactors were characterized for uniformity by ultrasonic C-scan and white light interferometry. Dynamic compression experiments were performed on a two-stage helium gas gun using the graded density impactors. Results will be presented and shown to agree well with hydrocode modeling.