Tantalum has excellent heat resistance (higher than 2500℃), corrosion resistance, excellent mechanical properties and good biocompatibility, so it has been widely used in capacitors, spattering targets, medical, aviation, military and other fields. Various industries are now looking for data on the physical properties of additive metal components to predict the strength and fatigue resistance of the material. Spherical tantalum powder was prepared by adding angular tantalum powder to plasma heat source, argon carrier gas to stabilize tantalum powder/plasma system, and hydrogen gas to improve tantalum heat transfer.
Diagonal and spherical tantalum powders were analyzed for chemical properties, fluidity and filling. The metal impurity in the powder was determined by inductively coupled plasma mass spectrometry, and the gas journal was determined by inert gas melting method. The morphology of the particles was studied by field emission scanning electron microscopy, and the fluidity and density of the powder were measured by Hall flow and apparent density methods. The data results show that compared with angular tantalum powder, spherical tantalum powder has better fluidity and packaging characteristics, which makes it exhibit better performance in LPBF printing bed.
Spherical tantalum powder was used as material to make tantalum rods under different conditions. The hardness and microstructure of the rods were analyzed. Under the condition of acid etching, it was characterized by metallographic microscope, and microhardness was tested by AMH32 software on the tester. Analysis of the data shows that oxygen impurities have a significant impact on the physical properties of printed tantalum parts. Under the condition of low oxygen impurities, tantalum parts show high ductility and strength.
The plasma heat source method was used to spheroidify diagonal tantalum powder. The physical properties of the powder were optimized under LPBF process to make its flow and filling uniform. The heat treatment of tantalum rod improves its elongation property, but the strength does not decrease significantly. Reducing the content of oxygen impurities to less than one part per million yields tantalum elongation similar to that of forged tantalum. In addition, the modulus of printed tantalum can be adjusted to match the bone modulus, and the optimization of powder properties and printing parameters allows it to adjust the physical properties of printed tantalum, which opens up new applications in fields such as medical, aerospace and defense.
