There are two main reasons for the large-scale application and development of composite materials and
titanium alloys. First, with the accumulation of practical experience in material research and application, the performance and reliability of materials are getting better and better. The second is that with the development of manufacturing technology, the price of the material itself is much lower than before. To be specific, we used to use
ti-6ai-4v (TC4) titanium alloy in the past. Now, while we continue to use it, we have developed new varieties of titanium alloy with higher strength and other properties. After years of tests, many parts of the aircraft have begun to use these new titanium alloys. For example, the Boeing 777 used Ti1023, 21S and Ti153 titanium alloys at the same time. This was the first time that these three titanium alloys were used in a civil aircraft at the same time.Ti1023 titanium alloy forgings used in landing gear of airbus A380 are 3.2 tons in weight and 4.2 meters in length, which is the largest titanium alloy forgings in the world at present. The unique properties of titanium alloy make its application prospect more extensive. In terms of artillery resistance, for example, the use of titanium alloy was significantly better than that of composite material. The amount of composite material used by the us f-22 fighter was reduced from 44.7% to 24%, while the amount of titanium alloy was increased to 41%.The usage of titanium alloy in military aircraft is more than that in civil aircraft. In addition, another new alloy with the characteristics of high fracture toughness and slow fatigue crack growth rate, namely the emergence of high-damage tolerance titanium alloy, is also an important reason for the increasing amount of titanium alloy on the aircraft.
