HRL engineer realizes 3D printing of high strength aluminum alloy

Metal based additive manufacturing or 3D printing is widely used in aerospace, biomedical and automotive industries Building metal components layer by layer can improve the design freedom and manufacturing flexibility, so as to achieve complex geometry, increase product customization, and shorten the time to market At the same time, it can eliminate the constraints of traditional economies of scale However, at present, only a few alloys can be used for printing, such as alsi10mg, tial6v4, CoCr, Inconel 718, etc Most of the more than 5500 kinds of alloys used now can not achieve 3D printing, because the melting and curing process in the printing process will produce the microstructure of large column grains and periodic cracks Recently, researchers at HRL lab announced that they have successfully developed a high-strength aluminum alloy (including al7075 and Al6061) that can be used for 3D printing The aluminum alloy stands out from thousands of alloys that are not suitable for 3D printing and is expected to become an ideal material for aircraft and automobile parts Relevant research papers were published in nature on September 21 Source of alloy additive manufacturing by laser hot melting: for the additive manufacturing of nature metal, alloy powder is usually added into the thin layer first, then heated to melting by laser or other heat sources, and finally solidified the thin layer In the past, if aluminum alloy such as al7075 or Al6061 with high strength and difficult to weld was used, the parts would have serious hot cracks, which made the metal parts show the same open state as flake biscuits "Our first goal is to figure out how to eliminate hot cracks," said Hunter Martin, leader of the research team By controlling the microstructure, we found that the problem should be the way the material solidifies " The solution of HRL is to introduce special zirconium based nanoparticles into the high-strength and difficult to weld aluminum alloy powder to obtain the functionalized alloy powder The team fed the alloy powder into the 3D printer, layered the powder, melted each layer by laser, and finally built the 3D object During melting and solidification, nanoparticles act as the nucleation site of the microstructure of the alloy to prevent hot cracks and keep the strength of the alloy unchanged Because the melting and curing process in additive manufacturing is similar to welding, this nano particle functionalization technology can also be used for welding alloy In addition, this technology has the advantages of expandability and low cost Source of aluminum alloy powder functionalized by nanoparticles: the HRL laboratory team said that the discovery of zirconium based nanoparticles is not easy They enlisted Citrine Informatics (A.I - driven material information analysis system) to find the right one among the possible particles "Using informatics is the key," said Brennan Yahata, another team leader In the past, metallurgy used to look for suitable alloy elements from the periodic table of elements, and then test them by trial and error The core of using informatics software is to use known nucleation theory to selectively search for materials with specific properties Big data analysis can narrow the range of material selection from tens of thousands to several " This new technology invented by HRL researchers can be extended to other alloy materials, such as high-strength steel and super nickel alloy, which are difficult to be obtained by the current additive manufacturing process, and open a new chapter for metal additive manufacturing in research, industry and national defense.