The Ministry of Education and Science of the Russian Federation’s National University of Science and Technology (NUST) conducted research to develop modifiers that help strengthen the stock material for 3D printing of complex aluminum composites for the aerospace industry.
By 3D printing with metal titanium and aluminum, researchers claim they are able to "double the strength of composites obtained by 3D printing from aluminum powder, and advance the characteristics of these products to the quality of titanium alloys.”
They note that titanium's strength is about six times higher than that of aluminum, and the density is 1.7 times higher. However, the 3D metal printing of titanium has been difficult to work with and posed safety concerns. It has often been avoided.
Doubling Down on Titanium Strength Using Aluminum Powder
Today, things could be changing based on some new research findings. NUST researchers say they developed modifiers for 3D printing that can be used to create products for the aerospace industry. They explain, “The developed modifying-precursors -- based on nitrides and aluminum oxides and obtained through combustion -- have become the basis of the new composite.”
For technical insight on the researchers’ work, visit the scientific journal Sustainable Materials and Technologies that published the findings.
As Alexander Gromov, who heads the NUST research group, explained, "We have developed a technology to strengthen the aluminum-matrix composites obtained by 3D printing, and we have obtained innovative precursor-modifiers by burning aluminum powders.”
Gromov and his team effort may be on to something big that will improve material strength, 3D printing with metals, and the utility of 3D printing as a means of developing and fabricating innovative products. He further explained:
Combustion products — nitrides and aluminum oxides — are specifically prepared for sintering branched surfaces with transition nano layers formed between the particles. It is the special properties and structure of the surface that allows the particles to be firmly attached to the aluminum matrix and, as a result, [doubles] the strength of the obtained composites.
Improving 3D Metal Printing
In the past, molding was the preferred method of fabricating parts. Innovations in 3D printing are offering new and effective methods. With 3D printing, manufacturers now have the tool to produce complex design components faster and ultimately much cheaper than traditional methods.
Speed remains one of the key advantages of 3D printing, as it eliminates many steps in the manufacturing process. These innovations were apparently used by researchers at Russia’s NUST to strengthen aluminum by combining the material with titanium.
The NUST researchers used two methods:
- Selective Laser Melting (SLM)
- Selective Laser Sintering (SLS).
Both involve the gradual layering of metal powder. As the layers increase in volume, a component is thus created. SLS and SLM are very similar. Both technologies use put additive manufacturing to the test by building up layers instead of removing material and are thus useful for building complex components. Some of these complex materials include spiral vents and nested cores.
Using these methods demonstrate the merit of additive manufacturing which has worked well on rare and expensive metals such as titanium, where possible.
A Conundrum of Metals
Titanium is a great choice if there’s a plausible way to use it in 3D printing. There are many advantages of using titanium as material for 3D printing, including:
- Complex shapes can be formed, which allows for many design possibilities.
- Parts printed with titanium also retain very good mechanical properties.
- 3D printing titanium does not create “impurities” unlike welds.
The facility of 3D printing speeds up the creation of materials, thus speeding up the manufacturing process. However, researchers had to overcome some technical challenges in working with titanium and aluminum.
Titanium is an optimal metal for fabrication; however, its use is dangerous. Titanium might be an ideal material for the aerospace industry, for instance, but it can be difficult to use the material for 3D printing due to fire and explosion hazards of powders.
Aluminum, on the other hand, is lightweight, moldable, and elastic enough for 3D printing. However, the material is not strong or solid enough.
It is said that the tensile strength for the alloy Duralumin is 500 MPa, and its Brinell hardness HB sits at 20 kgf/mm2.The crux of the findings has provided a path to combine the strength of titanium and the flexibility of aluminum to create the new materials for 3D printing.
Future Advances
3D printing with materials such as titanium holds much promise in other high-tech fields outside of automotive. Aerospace, medical, defense, and many other industries all stand to benefit from this subtle but not-so-subtle advancement in 3D printing of metals, namely the use of titanium in 3D printing with the use of aluminum powders.
