U.S. Researchers Develop Method for 3D Printing of High-Strength Aluminium Alloys
22 September 2017 by Staff
A research-and-development laboratory in California announced this week the development of a method for printing high-strength aluminium alloys into parts that meet the high tolerances necessary for use in the aerospace and automotive industries.
HRL Laboratories, LLC made the announcement on Wednesday, explaining that their new method for additive manufacturing allows for the use of high-strength aluminium alloys including AI7075 and AI6061. These alloys, which are commonly used in the aerospace and automotive sectors, have not yielded themselves to use in 3D printing prior to this breakthrough.
“We’re using a 70-year-old nucleation theory to solve a 100-year-old problem with a 21st century machine,” explained the team’s co-leader Hunter Martin.
According to the researchers, high-strength aluminium alloys suffer cracks when subjected to additive manufacturing processes, as the heat used in 3D printing makes the alloys brittle and flaky.
Researchers overcame this problem by adding zirconium-based nanoparticles into the powdered alloy. When the mix is layered on with a laser, the nanoparticles function as nucleation sites at which the alloys collect and solidify. This allows the alloys to harden and strengthen without experiencing the cracking that weakens the entire structure.
“Our first goal was figuring out how to eliminate the hot cracking altogether. We sought to control microstructure and the solution should be something that naturally happens with the way this material solidifies,” Martin explained.
In order to find suitable nanoparticles, researchers called upon informatics to simplify the search for an element that possessed the necessary characteristics.
“Using informatics was key,” said co-team leader Brennan Yahata. “The way metallurgy used to be done was by farming the periodic table for alloying elements and testing mostly with trial and error. The point of using informatics software was to do a selective approach to the nucleation theory we knew to find the materials with the exact properties we needed. Once we told them what to look for, their big data analysis narrowed the field of available materials from hundreds of thousands to a select few. We went from a haystack to a handful of possible needles.”
In addition to aluminium, researchers say the process may also make other metals that are not able to be joined under conventional welding techniques weldable for the first time.
Based in Malibu, HRL Laboratories is a joint venture between The Boeing Company and General Motors.