Manufacture of Bulk Nanocrystalline Tungsten Alloys

This proposal describes an innovation for making bulk nanocrystalline tungsten alloys that will be sufficiently ductile and meet mechanical properties targets set by the army. Tungsten (W) and its alloys are primary candidate materials for next generation munitions and warheads owing to its high density, high modulus, and other favorable properties such as benign environmental impact. The actual use of tungsten in these applications is however, very limited due to its low ductility and high ductile-to-brittle transition temperature (DBTT). Although nanocrystalline structure has been considered a very promising approach for achieving higher ductility in W and lower DBTT, it is very difficult to achieve nanoscale grain size after sintering due to rapid grain growth that occurs during densification. To meet this challenge, based on the extensive experience and expertise of Heavystone Laboratory LLC and its partner University of Utah on sintering of nanosized powders as well as properties of tungsten and tungsten alloys, Heavystone proposes to develop bulk nanocrystalline tungsten alloys with average grain size finer than 100 nanometer (nm) by using a novel low temperature high pressure processing technology in conjunction with alloying additives.