Due to the ideal strength and weight characteristics, the demand for high-temperature titanium alloys in the automotive and aerospace fields is increasing. However, the engineering weight ratio, complex structure, working temperature, and the development speed of titanium parts pose challenges to the traditional manufacturing process. Therefore, additive manufacturing technology has become a powerful tool for manufacturers to overcome this challenge.
The Italian BEAMIT Group announced on March 26, 2021 that it has developed an additive manufacturing process for titanium alloy Ti6242. The company said that Ti6242 can be used to manufacture components for racing and aerospace applications, and has better performance than alloys processed by traditional techniques.
BEAMIT's laser powder bed fusion (LPBF) 3D printing process can produce components with similar levels of tensile strength and heat resistance to other materials, but they are much lighter. According to the company, the newly developed process can also achieve sustainable benefits through waste prevention and powder recycling. Although other materials can be used in the racing field to achieve tensile strength similar to Ti6242, the weight is much greater. Ti6242 can replace parts made of nickel superalloys, such as exhaust devices and supersonic aircraft engine materials, reducing weight without losing strength.
3D printing Ti6242
Ti6242 has the characteristics of light weight and high tensile strength, can withstand temperatures up to 550°C, and can print complex shapes. BEAMIT started to develop Ti6242 additive manufacturing process suitable for LPBF processing in 2019. Ti6242 has high temperature resistance and can produce lightweight components without affecting the tensile strength. This makes the alloy an ideal choice for lightweight and high-performance components in the racing and aerospace industries. The BEAMIT team set out to optimize the mechanical properties of Ti6242 at high temperatures through the LPBF process, thereby achieving a tensile strength of up to 1kMPa and a density of 4.5 g/cm3.
Alessandro Rizzi, BEAMIT Group’s material and special process manager, said that this material is very suitable for laser powder bed fusion (LPBF), but the real focus is on heat treatment. The research team designed different vacuum cycles to optimize the mechanical properties at room temperature and high temperature, and developed an integrated high-pressure heat treatment process. Ti6242 alloy has a high strength-to-weight ratio of more than 600 MPa at temperatures up to 550°C, which makes the material an excellent choice for high mechanical strength and lightweight applications, and can replace steel and nickel super alloys.
After the BEAMIT team tested and compared the mechanical properties of 3D printed Ti6242 with conventional methods (such as forging) Ti6242 and another high-performance titanium alloy IMI834 parts, the performance of 3D printed components is better than traditional forged components. Ti6242 produced by LPBF has undergone solution heat treatment (above the β-transition temperature) and aging, and is characterized by tensile tests at room temperature and at 300°C, 550°C and 750°C. (Note: These alloys are generally used in applications up to 550°C; tests have been conducted at 750°C to explore their performance at higher than normal operating temperatures).
Application of 3D printing titanium alloy
In terms of automobiles, luxury car manufacturer Bugatti has used 3D printed titanium parts in some vehicles to reduce weight and improve the high temperature resistance of parts, including exhaust tail pipes of Chiron Pur Sport models, titanium alloy brake calipers and Bolide Titanium alloy front wing bracket for super sports car.
At the same time, 1016 Industries, a car modification expert, has merged titanium and carbon fiber 3D printing together. Integrate 3D printed performance parts into the ultra-lightweight version of the McLaren 720S sports car. Thanks to this technology, the weight of the special edition model is nearly 9% lighter than the original model.
Significant progress has also been made in the development of 3D printing titanium materials in China's aerospace industry. For example, SLM and SLS 3D printer manufacturer HSGK announced that their customer Aerospace HEHT has developed a new high-temperature titanium material TA32 specifically for the FS271M 3D printing system. Alloy parts can withstand a maximum operating temperature of 550 degrees Celsius, and have excellent tensile strength, flexibility and plasticity at high temperatures.
Abroad, American aerospace manufacturer Spirit AeroSystems has previously installed 3D printed titanium structural components on the front fuselage of the Boeing 787, and the US Air Force’s Hill Air Force Base has also successfully incorporated 3D printed titanium alloy brackets. The F-22 fighter jet manufactured by the aerospace and defense contractor Lockheed Martin.