Titanium p

Titanium p

Concept definition: titanium-based alloy is added to other elements of the alloy known as titanium. Titanium has a low density, high strength, corrosion resistance, good process performance, etc., is an ideal material for aerospace engineering structures.
Scope of the study: the structure of titanium and titanium alloys can be divided into heat resistant titanium, titanium alloy or α, β-type titanium alloys and α + β type titanium alloy. Scope of the study also includes forming technology of titanium alloys, powder metallurgy technology, rapid solidification technology, titanium and other military and civilian.

(1) the development process
In the early 1950s - early 1970s
Demand for power: To meet the needs of the aviation industry for materials, titanium and attention to the development of technology based primarily on metallurgy and technology.
Main features: This phase is characterized by the gradual shift from exploration and research applications of the material. The main materials are Ti-6Al-4V, Ti-5Al-2.5Sn, mainly for aircraft engines, space pressure vessel, such as the engine casing.
Typical results and products: Typical materials: Ti-6Al-4V, Ti-5Al-2.5Sn

70 years to 90 years
Demand for power: to expand the application fields of titanium, titanium industry has been developing rapidly, new technology and new technology to promote the development of titanium forming process.
Main features: This stage is characterized by: (1)titanium alloy increasing amount of applications in the aerospace industry and in other industries such as marine engineering, chemical, electric power, metallurgy, medical, and other applications are increasing, becoming the third metal. (2) new titanium continue to come out, such as high-strength titanium alloys, heat-resistant titanium alloy. (3) the use of new technology such as super plastic forming, rapid solidification technology and isothermal forging. (4) To expand the application emphasis on reducing costs.
Typical results and products: Typical materials: Ti-1100, Ti-1023, IMI834, Timetal62S, SP-700, etc.
(2) the current level and development trend
Titanium is used widely in the aerospace industry of a metal material, use can be divided into structural titanium and high temperature titanium alloy (use temperature> 400 ℃).
Titanium alloy Ti-6Al-4V to representatives, the alloy has been widely used on aircraft, missiles, and by the time the main load-bearing structural components turn structure. To accommodate the higher strength and toughness requirements (such as strength increased to 1275 ~ 1373MPa, strength increased to 29 ~ 33, the elastic modulus increased to 196GPa), developed in recent years, many new titanium alloy, such as the United States, Ti-15V-3Cr -3Sn-3Al; Ti-3Al-8V-6Cr-4Mo-4Zr (β-C), Ti-6Al-2Sn-2Zr-2Cr-2Mo-0.23Si, Ti-4.5Al-1.5Cr; British Ti-4Al -4Mo-2Sn-0.5Si (IMI500), Japan SPF00, CR800, SP700 and the former Soviet Union and other BT22. Where Ti-15-333 casting and β-C can be replaced precipitation hardening stainless steel and nickel-based alloys, Ti-6-22-22 in the United States Advanced Tactical Fighter (ATF) prototype F-22A in the accounts for 22% (by weight) . Japan's SP700 (Ti-4.5Al-3V-2Mo-2Fe), only high strength, and superplasticity at up to 755 ℃, elongation up to 2000%, good formability, low cost, can replace Ti-6Al-4V has been used in aerospace components.
High temperature titanium alloy made some progress in recent years in the field, the United States and Britain dominate. But the two methods used to develop and focus is different. The United Kingdom is the α-phase solid solution strengthening the necessary means for improving the creep strength without β phase coexistence approach, focusing on the study of nearly α type alloys, namely the development in order to improve the creep strength based Ti-4Al-2Sn- 4Mo-0.5Si (using temperature 400 ℃), Ti-11Sn-2.25Al-5Zr-1Mo-0.2Si (IMI679, use temperature 450 ℃), Ti-6Al-5Zr-0.5Mo-0.25Si (IMI685) alloys and to improve the fatigue strength based Ti-5.5Al-3.5Sn-3Zr-1Nb-0.3Mo-0.3Si (IMI829) and Ti-5.5Al-4.5Sn-4Zr-0.4Mo-0.8Nb-0.4Si (IMI834).
The United States is used to improve the fatigue strength at the expense of the creep strength of the method, focusing on high molybdenum content of the alloy studied, such as Ti-6Al-2Sn-4Zr-2Mo (6242, operating temperature 470 ℃), 6242S (using temperature 500 ℃) alloys. Subsequently, the research and development of the Ti-6Al-2.7Sn-4Zr-0.4Mo-0.45Si alloy (Ti-1100), which uses the temperature increased to 600 ℃.
Recently, the US has developed a Timetal21S (Ti-15Mo-2.7Nb-3Al-0.2Si) (also known as β21S), the use of temperature 704 ℃, the catheter can be used in the manufacture of high temperature and pressure pipes, are preferable for the US National Space Plane (NASP) metal matrix composite body with the matrix material. Currently, these new high-temperature titanium alloys are not yet entered the practical stage.
At present, high-strength titanium alloy superplastic forming technology has developed rapidly, the trend is forming isothermal forging pressure and vacuum forming.
The United States in the development and application of titanium alloy, has been in the lead, according to statistics in the US aviation industry, titanium shaft consumption ratio of 70%, the United States in terms of forming titanium alloy, the main use of isothermal forging superplastic conditions and sheet metal forming. To reduce costs, expand the application, the United States launched a new alloy grades, such as Timetal62S (Ti-6Al-2Fe-0.1Si), vanadium and iron in the cost of generation is better than Ti-6Al-V, and the performance is comparable.
Titanium industry over the former Soviet Union has 35 years of history, its development process smooth, no big ups and downs. Production of a large number of the Ti-6Al-4V and Ti-5Al-2.5Sn similar series of high-temperature high-strength alloy and alloy, and studied the special corrosion resistant alloys, such as 4200,4210,4207 and so on, in the aerospace industry, the former widely used in the Soviet Union under atmospheric pressure conditions titanium superplastic forming process.
Britain in research and application of heat resistant titanium alloys with the United States each aspect advantage, but its emphasis on research in recent α type alloys, namely to increase the creep strength and vigorously develop focused alloys such as Ti-4Al-2Sn-4Mo-0.5Si , Ti-11Sn-2.25Al-5Zr-1Mo-0.2Si (IMI879), Ti-6Al-5Zr-0.5Mo-0.25Si (IMI685), among IMI685 has been widely used in Europe.
In recent years, the Japanese in the study of titanium has also made great progress, such as to reduce the cost of developing the SP-700 (Ti-4.5Al-3V-2Mo-2Fe) alloy, forming properties of the alloy than Ti-6Al -4V. Japan's low strain rate superplasticity vacuum forming process.