Effect of Ta on the microstructure and mechanical properties of W Ta alloys prepared by arc melting

Herein, W–xTa alloys (x = 0, 10, 20, 30, 40, and 50 wt%) were fabricated using the arc-melting method to improve the strain capacity of tungsten. The effects of Ta on the microstructure and mechanical properties of the fabricated alloys were investigated. The WTa alloys with different Ta contents formed a single-phase WTa solid solution after arc melting, and their average grain size changed from 1056 to 243 μm with increasing Ta content, indicating a grain refinement effect. The hardness, compressive strength, and compressive strain of W improved after the addition of Ta, with the compressive strength and compressive strain of W40Ta reaching 1.63 GPa and 9.54%, respectively, thus achieving the best comprehensive mechanical properties. The fracture surface diagram suggested that a mixed fracture mode of intergranular fracture and transgranular dissociation fracture gradually formed with the increasing of Ta content. Transmission electron microscopic analysis showed that the dislocation density of the compressed W40Ta alloy increased considerably compared with that of pure W, edge dislocation slip was also found to be an important slip mechanism in addition to screw dislocation slip. This study provides insights into the performance optimization, reinforcement design, and strengthening mechanisms of W–xTa alloys.