Tantalum tungsten alloys bar and its production method
In recent years, with the development of aviation, aerospace and atomic energy industry, especially the development of supersonic aircraft and returnable hypersonic space vehicle with 4-6 Mach number, the requirements for surface skin materials and high temperature structure materials in the engine are becoming higher and higher. Tantalum metal, especially tantalum alloy, such as tantalum tungsten alloy can be used as heat-resistant and high-strength structural materials of supersonic aircraft, rockets and missiles, as well as parts of control and adjustment devices. The melting point of tantalum tungsten alloy is 3080 V, and it has high temperature toughness and impact resistance. The highest service temperature can reach 2500°C in vacuum environment. It can be used as the surface skin, combustion chamber, missile engine nose vertebra, nozzle, exhaust pipe and other important parts in some positions of spacecraft. Tantalum 10 tungsten alloy belongs to the alloy with high tungsten content among tantalum and tungsten alloys. Tungsten is infinitely solidly soluble in tantalum as an alternative continuous solid solution, which mainly plays a role of solid solution strengthening. However, when the tungsten content reaches 14% and 16%, the properties will not be significantly increased. With the increase of tungsten content, the brittleness of the material also increases, and brittle cracking is easy to occur in the process of pressure machining. Because it is easy to crack in the process of processing, the ingot should not only fully break the bad microstructure in the casting state through hot forging, but also ensure the reasonable hot forging temperature and processing rate. Therefore, the selection and matching of hot working technology and forging technology of tantalum-tungsten alloy is the key point of the material processing. Through the implementation of reasonable technology, it is necessary to ensure that the material does not crack and fail in the process of processing, and to ensure that the microstructure is small and uniform, so as to avoid the deformation, crack and failure caused by the microstructure defects in the high temperature and high pressure operating environment, so as to make it suitable for the tantalum-tungsten nozzle used in aeroengines. In order to satisfy the operating requirements of aircraft engine tantalum ten tungsten nozzle, existing technology mainly adopts the following method preparation of tungsten tantalum ten secondary vacuum electron beam furnace smelting for phi is 97.5 mm outside diameter specifications of ten tungsten tantalum ingot casting, casting by fixed power of medium frequency induction heated to high temperatures, the forging method with the method of drawing long, namely get ten tungsten tantalum rod. However, the casting structure of the forging billet obtained by the above forging process has a low degree of breakage and the internal bad structure is not completely eliminated, which leads to the quality problem of fracture failure caused by local deformation under high temperature and high pressure.