Titanium alloy-an important material for China's aerospace

Titanium alloy research background

In February 1956, the Politburo meeting of the Central Committee of the Communist Party of China passed the resolution "Instructions of the Central Committee of the Communist Party of China on Intellectuals". According to the spirit of the meeting, the "1956-1967 National Science and Technology Development Plan" was compiled. In the 12-year science and technology development plan, 572 key scientific research tasks have been identified, of which 72 are the most important research projects. Titanium alloy research is one of these 72.

On New Year's Day in 1957, the Titanium Alloy Laboratory was formally established.

Introduction to Titanium Alloys

Titanium is widely distributed, and its content exceeds 0.4% of the mass of the earth's crust. The global proven reserves are about 3.4 billion tons, ranking tenth among all elements (oxygen, silicon, aluminum, iron, calcium, sodium, potassium, magnesium, hydrogen). ,titanium). In 1895, H. Moisson reduced TiO2 (primary ore titanium) with carbon in an electric arc furnace to obtain titanium with a purity of 98%, but at that time, people believed that titanium was an unprocessable and brittle metal. In 1910, M. Houter produced 99.5% pure titanium by sodium reduction method, which can be processed at high temperature, but it is still very brittle at normal temperature and cannot be processed. In 1925, A.E.Van Arkeld used titanium iodide decomposition method to obtain titanium with a purity of 99.9%. It can be processed at room temperature, but the output is small and cannot be industrialized. In 1940, W. Kroll used magnesium to reduce TiCl 4 to obtain sponge titanium, which made titanium available for industrial production. In 1948, Luxembourg scientists invented the "magnesium method" (without reduction of TiCl4) used in the production industry in the United States before it started. Titanium is 40% less dense than steel, and the strength of titanium is equivalent to steel, which can improve structural efficiency. At the same time, titanium has good heat resistance, corrosion resistance, elasticity resistance and processability. So it was used in the aviation industry as soon as it appeared. The most important and most widely used main material of the space shuttle. The research of titanium alloys for aviation has always been an important branch in the aerospace field.

Development and application of titanium alloys for aviation

In the 1950s, military aircraft entered the supersonic era. The original Lu steel structure can no longer meet the new needs, and the industrial development of titanium alloys is very capable of meeting the needs of this era. Titanium alloy has low density, high specific strength, corrosion resistance, high temperature resistance, non-magnetic, wide use temperature, and can be used for various parts. The fourth-generation American F22 engine uses 40% titanium (mass fraction), and its F19 engine uses 39% titanium.

Application of China's titanium alloy aeroengine

In 1964, a research and development project for the material Ti-6Al-4V (90% titanium, 6% aluminum, 4% vanadium) was established. The engine rotates very fast, more than 10,000 revolutions per minute, with great centrifugal force and excellent fatigue performance. Stainless steel is heavier, the specific gravity is about 7.9, titanium is about 4.5, the specific strength is higher, and the centrifugal force is also small. If titanium alloy is used, the weight of the aircraft can be reduced. The first test-run engine equipped with titanium alloy blades in our country was the No. 654 turbojet 6 engine. In 1979, the Ministry of National Defense decided to equip the Air Force with new fighters such as the J-8II. The engine used in the new model is the turbojet 13 series, and the amount of titanium alloy accounts for 13% of the total structural weight.