Hot workability and industry application of titanium alloy

TC4 titanium alloy is also called Ti-6Al-4V, this type of alloy contains 6% Al and 4% V. TC4 is widely used in titanium alloys. Al is an element that improves the stability of the phase, and V is an element that improves the stability of the β phase. After adding aluminum to pure titanium, aluminum has sufficient solubility in a-Ti. Aluminum is widely distributed in nature, easy to prepare, and relatively cheap. Aluminum is much lighter than titanium. Adding aluminum to titanium reduces the density and increases the specific strength. More importantly, aluminum can effectively solid solutions strengthen while the alloy maintains sufficient plasticity. Aluminum can effectively strengthen the a-phase not only at room temperature but also at high temperatures, improving the thermal strength and working temperature of the titanium alloy. 6al4v titanium round bar with 6% aluminum can work for a long time at 400℃ and maintain high strength. However, only aluminum-containing titanium aluminum alloy (Ti-4Al) will become brittle after long-term heating at 550°C. Therefore, adding an appropriate amount of β-type stabilizing element X to the titanium aluminum alloy will hinder the formation of brittleness, and contains a certain amount of β phase, which improves the hot workability of the alloy and the plasticity of the alloy, and it can also be heat treated ( Such as solid-solution + aging to further improve the strength). The structure of TC4 deformed and annealed is a+β coexistence. The content of the β phase in TC4 is relatively small, accounting for about 10%. TC4 alloy has good overall mechanical properties after being air-cooled (recrystallization annealing) after being kept at 750~800℃ for 1-2h. The structure of the alloy at this time is equiaxed a+β phase.

6al4v titanium bar can usually be solid-solution + aging strengthening heat treatment, such as heating at 913~940℃ for 1h, water quenching +523~550℃ for 3~4h, after air cooling, the strength can be increased by 20%~25%, but the plasticity is slightly declined. However, the current domestic TC4 is mainly used in the annealed state, and it is rarely used in the strengthened heat treatment state. The high-temperature strength of TC4 is greatly improved due to the addition of aluminum.

TC4 titanium alloy is suitable for manufacturing various jet engine compressor blades, impellers, etc. Petroleum machinery parts, ultrasonic molds, ultrasonic welding heads, etc.