Dynamic deformation behavior of an oxide-dispersed tungsten heavy alloy fabricated by mechanical alloying

The objective of this study is to investigate the dynamic deformation and fracture behavior of an oxide-dispersed (OD) tungsten heavy alloy fabricated by mechanical alloying (MA). The tungsten alloy was processed by adding 0.1 Wt pct Y2O3 powders during MA, in order to form fine oxides at triple junctions of tungsten particles or at tungsten/matrix interfaces. Dynamic torsion tests were conducted for this alloy, and the test data were compared with those of a conventional liquid-phase sintered I(LPS) specimen. A refinement in tungsten particle size could be obtained after MA and multistep heat treatment without an increase in the interfacial area fraction between tungsten particles. The dynamic test results indicated that interfacial debonding between tungsten particles occurred over broad deformed areas in this alloy, suggesting the possibility of adiabatic shear-band formation. Also, oxide dispersion was effective in promoting interfacial debonding, since the fine oxides acted as initiation site for interfacial debonding. These findings suggest that the idea of forming fine oxides would be useful for improving self-sharpening and penetration performance in tungsten heavy alloys.