High-Temperature Mechanical Properties of TaWHf Alloy Doped with Re and C

The high-temperature mechanical properties of Ta-8W-2Hf alloy doped with Re (1wt%) and C (0.01wt%) were investigated at room temperature, 1300 ° C, and 1500 ° C. Results show that fine and dispersed precipitates Ta₂C are detected in crystallized TaWHfReC alloy, which significantly enhance mechanical properties of the alloy. The strength of TaWHfReC alloy is much higher than that of TaWHf alloy, especially at 1300 and 1500 °C. At 1300 °C, the ultimate tensile strength of the TaWHf alloy is 322 MPa, while that of the TaWHfReC alloy reaches 392 MPa. When the temperature rises to 1500 ° C, precipitated-phase strengthening remains effective in the TaWHfReC alloy, achieving an ultimate tensile strength of 268 MPa. Additionally, at 1300 °C, the elongation of the TaWHfReC alloy reaches 23.5%, which is nearly twice of that of the TaWHf alloy. The significant improvement in the mechanical properties of the TaWHfReC alloy at elevated temperatures is primarily attributed to the interaction between dislocations and the fine Ta₂C precipitated phase. The fine and uniformly distributed particles effectively inhibit dislocation motion and exhibit a pronounced strengthening effect at high temperatures.