Tantalum and tantalum alloy have been used in many high-tech fields such as aerospace, metallurgy, chemical industry and nuclear industry because of their excellent chemical stability, high temperature mechanical properties, corrosion resistance and processing and forming ability.
Tantalum and tantalum alloy have excellent mechanical properties and wide application range, which has caused extensive research on their mechanical properties by scholars at home and abroad. At present, the main methods to improve the mechanical properties of Ta alloy are: (1) alloying strengthening by alloying elements; (2) grain refinement strengthening (3) ceramic phase strengthening. High strain rate mechanical tests were carried out on Ta and Ta-2.5W alloy, and the material constitutive relationship was established based on the relevant test data, which effectively quantified the sensitivity of material deformation to temperature and strain rate. The results show that, compared with Ta, the flow stress of Ta-2.5W alloy increases obviously at room temperature and high temperature, and the sensitivity of the deformation process to temperature and strain is effectively reduced. Therefore, adding an appropriate amount of W element to Ta can improve the mechanical properties of Ta-W alloy at room temperature and high temperature.
The mechanical properties of Ta-2.5W, Ta-5W and Ta-7.5W alloys at room temperature were systematically studied by increasing the content of W in Ta-W alloys. The results show that adding appropriate amount of W can enhance the solid solution strengthening effect of Ta matrix and improve the comprehensive mechanical properties of TA-W alloy at room temperature effectively. However, when W is added excessively, the susaturated W element will be enriched in the grain boundary region, forming a W-rich brittle second phase, which significantly deteriorates the comprehensive mechanical properties of Ta alloy at room temperature. However, under high temperature conditions, TA-W with high W content has a better use effect. Therefore, the actual application environment should be considered in the material preparation, and the strengthening elements should be reasonably added to effectively regulate the mechanical properties of the material.
The results show that with the increase of W content, α texture is enhanced and γ texture is weakened in Ta-W alloy. However, because the γ texture is more likely to form shear bands during deformation, the shear band density of Ta-2.5W alloy is much higher than that of Ta-10W alloy under the same strain conditions, showing more excellent plastic deformation ability. In addition, the addition of W has an important effect on the cross-slip ability of the dislocation, which is reflected in the fact that more dislocation rings, activated slip systems, and larger dislocation cells can be seen in the Ta-2.5W alloy compared to the Ta-10W alloy. Therefore, the matrix mechanism of W strengthening Ta alloy is to inhibit the sliding of dislocation, thereby increasing the strength of the alloy, but also reducing the plastic deformation ability of the alloy.
