Titanium and titanium alloy is a kind of metal material with corrosion resistance, high specific strength and good biological affinity.Because aviation, aerospace domain USES titanium demand more, because this titanium alloy is used in this respect widely known.It can also be used in general industrial products, such as titanium for surgical implants, and titanium alloys have attracted much attention in medical devices.Although titanium alloy can be processed into a variety of industrial products, but its demand is not high.This is due to the manufacturing cost of titanium alloy and the high processing cost of titanium alloy products, leading to the higher final product price.Therefore, to increase the demand of titanium alloy products, it is necessary to reduce the production and processing cost of titanium alloy, which is a long-term task.But the task is getting easier.
Among the low-cost reduction of titanium alloy, the most important is the low-cost reduction process from titanium ore to titanium metal. At present, various direct reduction methods and continuous reduction methods of titanium are under study.
In this paper, the low-cost design of titanium alloy and the low-cost processing technology of titanium alloy are summarized.
Low cost technology of production process
In the production of titanium alloy products, the processing cost represented by cutting and grinding is quite high. Therefore, it is very important to develop low-cost processing technology by using the low-cost alloy. It is difficult to bend titanium alloy, which is represented by Ti-6Al-4V alloy. In order to prevent oxidation, heating must be carried out in inert gas and vacuum environment. At the same time, the microstructure changes significantly after heat treatment, so it is necessary to establish a reasonable heat treatment process. At present, although large forging equipment has been introduced into China, the stable operation of the equipment still needs time, and the production of large parts will also require more cutting. Therefore, it is very important to reduce the machining amount of titanium alloy, and it is also necessary to establish the joining method for assembling large parts. In general, the effective methods to reduce titanium alloy cutting are powder metallurgy, metal powder injection molding (MIM), laser molding, electron beam deposition molding (EBM) and other near net forming methods. It is also necessary to establish effective laser welding, friction stir welding (FSW) and other new joint technologies. In addition, the efficient and effective bending technology to reduce the difficulty of bending is also expected to be established. In addition, it is necessary to control the microstructure to improve the properties when using the low-cost titanium alloy. Therefore, it is necessary to establish appropriate heat treatment technology.
Compared with the traditional alloy, the low-cost titanium alloy can be processed at low temperature to reduce the processing cost. In the commonly used Ti-6Al-4V alloy plate, several plates are overlapped, and the steel plate is wrapped outside for hot processing (this method is called cladding processing), which leads to high cost.
The low-cost titanium alloy extrusion material adopts the bending processing technology of local heating, and the forging is expected to realize the low-cost production of aircraft parts through the combination of machining technology and welding technology (such as laser welding). To sum up, in the low cost of titanium alloy, the near net forming method of titanium alloy powder attracts more and more attention. MIM method is suitable for the production of small parts, and it is expected to realize the production of various alloys. The relationship between tensile strength and ductility of Ti-6Al-4V alloy was obtained by adding Fe, Cr and Mo into the alloy by MIM method. By adding these elements, the strength of Ti-6Al-4V is improved. Under certain conditions, the tensile strength and ductility of more than 1000MPa and more than 10% can be obtained.
Recently, the electron beam lamination method has attracted much attention. The appearance of Ti-6Al-4V alloy implant with bone conduction function was made by electron beam lamination. It is possible to produce such a complex product directly by electron beam lamination.
The subject of low cost titanium alloy can be considered as follows:
1. Reduction of smelting cost
(1) continuous development of Kroll smelting method and new smelting method (direct reduction method)
(2) improve the purity of titanium with high o content produced by direct reduction
(3) improve the properties of titanium with high Fe content produced by continuous Kroll Process
2. Low cost of processing technology
(1) low cost of plastic processing technology
(2) low cost of cutting process
(3) application of near net forming: reduce cutting amount and machining amount of materials
3. Design and development of low cost alloy
(1) reduction of high cost alloy elements
(2) utilization of low cost replacement elements
(3) utilization of low cost invasive light elements
(4) utilization of recyclable materials
4. Improve performance by controlling organizational structure
5. Develop application fields
The low cost of titanium alloy must solve the above problems, which will take a long time to solve. By working hard to solve the above problems, the low cost of titanium alloy will be realized eventually.