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Current titanium alloys used in additive manufacturing often cool and bond together in column-shaped crystals during the 3D printing process, making them prone to cracking or distortion. Unlike aluminium or other commonly-used metals, there is no commercial grain refiner for titanium that manufacturers can use to effectively refine the microstructure to avoid these issues.
Now, however, a new titanium alloy with copper might have solved the problem. Professor Mark Easton from RMIT University in Melbourne, Australia, said a new titanium-copper alloy printed with “exceptional properties” without any special process control or additional treatment.
“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,” he said.
“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.”
The collaborative project involved leading researchers in the area of alloy composition and grain microstructure from RMIT University, CSIRO, the University of Queensland and the Ohio State University.
Similar metal systems could be treated in the same way to improve their properties, said CSIRO senior principal research scientist Dr Mark Gibson.
“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.”
The new breed of alloys could increase manufacturers' production rates and allow for more complex parts to be made, said Dr Gibson.
“It opens up the possibility of developing a new range of titanium-based alloys specifically for 3D printing,” he said.
The research was published in Nature.
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