A Comparison of the Deformation Flow and Failure of Two Tungsten Heavy Alloys in Ballistic Impacts

Ballistic tests were conducted with sub-scale long rod penetrators of two different processing conditions of the same tungsten heavy alloy. The liquid-phase sintered composite of 90% tungsten-9% nickel-1% cobalt (by weight) was tested in its low strength, as-sintered and heat-treated condition, and in a high strength, 50% cold-worked (by swaging) and aged condition. Small, but consistent, differences in the ballistic performances of the two lots of penetrators were observed in depth of penetration tests, in thick armor steel targets, and in limit velocity determinations against finite thickness steel targets. Metallographic examinations were conducted on the residual penetrators recovered from sectioned steel targets. Using the tungsten particles in the nickel alloy matrices of these residual penetrator materials as embedded strain gauges, the strain distributions, deformation gradients, and flow and failure behaviors of these two tungsten heavy alloy lots were examined. Correlations were sought between the flow and failure behaviors of these two lots and their ballistic performances. Presented at the International Conference on Tungsten, Refractory and Hardmetals (6th), held in Orlando, FL, on 7-8 Feb 2006. Published in the Proceedings of the International Conference on Tungsten, Refractory and Hardmetals (6th), p350-358. The original document contains color images.