Microstructure and mechanical properties of W-10 wt-%Ta alloys prepared by spark plasma sintering

The brittleness of tungsten (W) is a key factor that affects the preparation and application of high-performance tungsten alloys. Tantalum (Ta), which can form a complete solid solution with tungsten, was expected to improve its dislocation mobility and toughness. In the W-10 wt-%Ta alloys prepared by spark plasma sintering, the amount of Ta solid dissolved in tungsten increased gradually upon increasing the sintering temperature. The compressive strength of W-10 wt-%Ta alloys first increased and then decreased by increasing the sintering temperature. The solid solution of tantalum constructed a large number of defects and edge dislocations in the tungsten structure. This result is surprising because plastic flows are generally controlled by screw dislocations in Body-Centered Cubic (BCC) metals and dilute alloys.