Application of high temperature titanium alloys

High-temperature titanium alloys have been widely used in aero-engines due to their excellent thermal strength and high specific strength. High-temperature titanium alloys are mainly used in fans and compressors of aero-engines, such as compressor discs, blades, navigators, connecting rings, etc. Replacing the original nickel-based superalloy with titanium alloys can reduce the weight of the compressor by 30%-35%. The proportion of titanium used in foreign advanced aero-engines reaches 25-39%. For example, the titanium alloy content of the F100 engine accounts for 25% of the total engine weight, the V2500 engine is 31%, and the F119 engine is 39%. The development demand of high-performance aero-engines has led to the development of high-temperature titanium alloys, and the operating temperature has gradually increased, from 400 °C represented by Ti-6Al-4V alloy in the 1950s to 600 °C represented by IM834 alloy. Above 600°C, the sharp decline of creep resistance and high temperature oxidation resistance are the two main obstacles restricting the development of titanium alloys to higher temperatures. Therefore, 600°C is considered to be the "thermal barrier" temperature for the development of titanium alloys. Over the years, in order to meet the needs of high-performance aero-engines, developed countries in the aviation industry such as Europe, America and Russia have attached great importance to the research and development of high-temperature titanium alloys, and have successively developed high-temperature titanium alloys used at 350-600 °C. The former Soviet Union developed titanium alloys of BT6, BT3-1, BT18, BT9 and other grades in the late 1950s, and developed BT18 and BT25 alloys in the 1960s and 1970s. Since then, in order to improve the performance and working life of high-temperature titanium alloys, high-temperature titanium alloys of BT18y, BT25y, BT8M, BT8-1 and BT8M are improved and developed on the basis of the original alloy. In recent years, BT36 titanium alloy has been developed, which are used in HKB, IIC90A and other engines respectively. Similarly, the United States also uses Ti64, Ti811, Ti6242 and other titanium alloys in advanced engines such as JT90 and F-110, respectively.