SBIR-STTR Award

The concept of using high-density body centered cubic (bcc) tantalum metal for explosively formed penetrators (EFP) continues to receive considerable interest in the defense community, in spite of variations in metal composition and properties. Alloying with a sufficient amount of tungsten (such as Ta-2.5%W) can diminish this sensitivity to slight changes in composition. In addition, the Ta-2.5%W alloy offers higher strength compared to pure tantalum, resulting in greater EFP penetration performance. In summary, the Ta-2.5%W alloy offers the EFP designer the advantages of the high-density pure tantalum with the enhanced strength and consistency offered by the alloy.The objectives of this proposed project are to determine the processing parameters required to provide uniform (111) texture and fine grain microstructures in cold forged tantalum-tungsten alloy (Phase I), and to demonstrate the producibility of 9-inch diameter EFP's (Phase II). Following the optimization of processing and resulting material properties, several EFP's would be produced for testing.Success of this program (Phases I and II) would provide the armament directorate with the ability to obtain 9-inch EFP's with improved penetration capability and quality consistency.

Keywords:
TEXTURE TANTALUM ANNEALING COLD FORGING RECRYSTALLIZATION TANTALUM-TUNGSTEN ALLOY

The concept of using high-density body centered cubic (bcc) tantalum metal for explosively formed penetrators (EFP's) continues to receive considerable interest in the defense community in spite of variations in metal composition and properties. Alloying with a sufficient amount of tungsten (such as Ta-2.5%W) can diminish this sensitivity to slight changes in composition. In addition, the alloy offers higher strength compared to pure tantalum, resulting in greater EFP penetration performance. The cold forging process offers additional benefits in the form of controlled crystallographic texture for higher through-thickness strength, as well as excellent uniformity of properties around the circumference of the part.Phase I has demonstrated that the texture of the tantalum-tungsten alloy can be controlled in a similar manner to that of pure tantalum. The Phase II effort will define the processing parameters required to produce 9-inch diameter plates (domed as well as flat) by the cold forging process, and will provide complete material characterization in the as-forged condition. Several 9-inch plates will be supplied to Eglin for evaluation during Phase II.Success of this program would provide the armament directorate with the ability to obtain 9-inch near-net-shape forgings with improved strength and uniformity.

Keywords:
TANTALUM TANTALUM-TUNGSTEN ALLOY RECRYSTALLIZATION TEXTURE ANNEALING COLD FORGING