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 and strengthening;
(3) ceramic phase strengthening.
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 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 addition of W has an important effect on the cross-slip ability of the dislocation, which is manifested by more dislocation rings, activated slip systems, and larger dislocation cells in the Ta-2.5W alloy than in 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.
The results show that the Ta-W alloy with high W content has better mechanical properties at high temperature under the same process conditions. However, the high content of W easily leads to the segregation of W element, which makes the mechanical properties of the alloy poor at room temperature. If the W element segregation problem can be solved, it will undoubtedly have great significance for expanding the application field of Ta-W alloy.
