Since titanium has long been considered one of the most suitable materials for metal 3D printing, its scope of application is now quite large, such as implants used in the medical industry and various aerospace parts. But the horror of this situation will not change much, because a study by Carnegie Mellon University (CMU) shows that 3D printing of titanium objects may lead to what is called “a rather fatal flaw.”
The shortcoming is simply that 3D printed titanium objects may have cracks due to numerous tiny pores inside, which are mainly due to the mixing of titanium metal powder into the gas after 3D printing.
CMU uses high-intensity synchrotron radiation X-ray and micro-tomography tools from the US Department of Energy’s Argonne National Laboratory to analyze electron beam melting (EBM) and selective laser melting. The titanium metal used therein is the most common Ti-6Al-4V.
According to their observations, the pore sizes in these titanium parts vary from a few microns to a few hundred microns, but they are numerous and randomly distributed, so it is very likely to cause internal cracks when subjected to a certain degree of external force.
In addition, CMU’s research team also found factors that affect porosity, mainly laser beam power, speed and spacing for 3D printers. In the experiments using EBM technology and Ti-6Al-4V, although they constantly adjusted the above parameters, they never completely eliminated the pores inside the print.
This is undoubtedly a heavy blow to the current 3D printing industry using titanium. It is important to know that metal (especially titanium) 3D printing has many advantages (such as high molding speed, high degree of freedom, more material saving, lower cost, etc.).
However, this does not mean the end of the world, because CMU researchers have found that while it is almost impossible to completely eliminate the pores in 3D printed titanium parts, there is likely to be a “dessert” between the un-melted powder and too much powder, which can make 3D printed titanium. The metal works best. Therefore, they have now turned their research to the initial state of titanium in powder.