A team of scientists from RMIT University (Melbourne, Australia) has announced successful trials of titanium-copper alloys for 3D printing in a movement towards kickstarting high-performance alloys for aerospace, defense and medical device applications.
The team reports that titanium alloys currently available to 3D print often cool and bond in column-shaped crystal during the printing process, which may lead them to crack or distort. Furthermore, commercial grain refiners for titanium are lacking, preventing manufacturers from refining the microstructure to avoid these issues.
The RMIT team claims a novel titanium-copper alloy, described in Nature, has solved these problems.
Mark Easton, Professor at RMIT University’s School of Engineering, explained that the alloy, 3D printed with “exceptional properties”, was printed without any additional process control or additional treatments:
Of particular note was its fully equiaxed grain structure: this means the crystal grains had grown equally in all directions to form a strong bond, instead of in columns, which can lead to weak points liable to cracking.”
Alloys with this microstructure can withstand much higher forces and will be much less likely to have defects, such as cracking or distortion, during manufacture,” Easton continued.
Furthermore, there is evidence to suggest that similar metal systems could be treated in the same way to improve their properties, as Mark Gibson, Senior Principal Research Scientist (Commonwealth Scientific and Industrial Research Organization; Canberra, Australia) explained:
Titanium-copper alloys are one option, particularly if the use of other additional alloying elements or heat treatments can be employed to improve the properties further. But there are also a number of other alloying elements that are likely to have similar effects. These could all have applications in the aerospace and biomedical industries.”
In general, it opens up the possibility of developing a new range of titanium-based alloys specifically developed for 3D printing with exceptional properties. It has been a delight, as it has been my good fortune for some time, to work on such an interesting and significant project as this with such a talented band of scientists.”
Sources: Zhang D, Qiu D, Gibson MA, Zheng Y, Fraser HL, StJohn DH, Easton MA. Additive manufacturing of ultrafine-grained high-strength titanium alloys. Nature. 576, 91–95 (2019); www.rmit.edu.au/news/all-news/2019/dec/3dprinting-titanium-copper