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 f racture 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 jun ctions of tungsten particles or at tungsten/matrix interfaces. Dynamic tors ion tests were conducted for this alloy, and the test data were compared wi th those of a conventional liquid-phase sintered I(LPS) specimen. A refinem ent in tungsten particle size could be obtained after MA and multistep heat treatment without an increase in the interfacial area fraction between tun gsten particles. The dynamic test results indicated that interfacial debond ing between tungsten particles occurred over broad deformed areas in this a lloy, suggesting the possibility of adiabatic shear-band formation. Also, o xide dispersion was effective in promoting interfacial debonding, since the fine oxides acted as initiation site for interfacial debonding. These find ings suggest that the idea of forming fine oxides would be useful for impro ving self-sharpening and penetration performance in tungsten heavy alloys.