Researchers have developed a method by which it is possible to 3D-print high-quality metal alloys such as aluminium. This allows these materials, often used for heavy industrial parts, to be produced faster and more economically than ever before.
Metal-based manufacturing has long been difficult and costly. High-performance, high-strength aluminium alloys are difficult materials to work with in additive manufacturing. Researchers at the company HRL Laboratories (based in Malibu) have devised a new method that makes it possible to 3D print this material quickly. In addition, the method also allows welding of material that was previously unweldable.
Nucleation
'We are using a 70-year-old nucleation theory to solve a 100-year-old problem with a 21st-century machine,' said Hunger Martin, engineer at HRL's 'Sensors and Materials Laboratory' in a press release. The HRL scientists call the method nanofunctionalisation, where nanofunctional powders are put into a 3D printer. This is applied in thin layers that are heated by a laser to solidify it into a three-dimensional object. During melting and solidification, structures produced this way do not crack and are able to retain their full alloy strength. This is due to the nano-particles acting as nucelation sites for the intended alloy microstructure.
'Our first goal was to figure out how to eliminate hot cracking altogether. We were looking at controlling the microstructure and the solution should be something that happens naturally with the way this material solidifies.'
Precious
High-grade alloys such as aluminium - including types such as AI7075 and AI6061 - are currently widely used in the production of aerospace and automotive parts, such as aircraft fuselages. However, existing methods are very costly and, with this, it is also not possible to ensure finer manipulation of these materials.
With this new nanofunctionalising technique that is easily scalable, it is possible to 3D-print high-quality alloys of all shapes and sizes. This enables faster, cheaper and more detailed production of these materials. In addition, because melting and solidification in 3D printing is akin to welding, the technique makes it possible to weld previously non-weldable alloys.
To determine which parts had the properties they needed, the HRL team enlisted the help of Citrine Informatics, a company that has developed an operating system for materials and chemicals. 'The reason for using this software was to take a selective approach to nucleation theory to find the materials with the exact properties we needed' says HRL's Brennan Yahata. 'Once we had passed on what we were looking for, their data analysis reduced the number of available materials from thousands to a few. The software helped us search for a needle in a haystack.'
By: Kelly Bakker
Source: HRL
