With the help of Citrine Informatics’ Citrination platform, scientists at University of California Santa Barbara and HRL Laboratories, a joint venture of General Motors and Boeing, have solved a long-standing challenge hindering the wide use of aluminum alloys in 3d printing. In particular, the high-strength aluminum alloys of relevance to the aerospace and automotive industries have notoriously remained impossible to 3d print due to a stubborn problem called hot cracking. In a study published in Nature, one of the world’s most prestigious scientific journals, the researchers employ a combination of metallurgical expertise and Citrination to design a robust solution to hot cracking.
Describing the breakthrough, John Martin, a scientist at HRL Laboratories, says, “We took an unweldable old metal and made it weldable.” How? The team started with a strong scientific hypothesis grounded in well-established metallurgical principles. They reasoned that the introduction of highly tailored grain refiners, a tried-and-true route to improve processability and properties of alloys, could make existing commercial aluminum alloys amenable to 3d printing.
However, testing this hypothesis presented an enormous challenge. The team would have to sift through millions of combinations of candidate grain refiners and target aluminum alloys to find ideal matches. This crucial step, for which no other software solution existed, is where Citrination came in. Brennan Yahata, another scientist on the study, notes, “Using informatics was key. The point of using [Citrination] was to do a selective approach 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.” Specifically, the authors of the study used Citrination to search millions of candidate materials combinations to find optimal sets of four key properties for which they were screening. When they tested these optimal combinations in the laboratory, the scientists found that the resulting parts had dramatically higher strength than had been demonstrated previously in 3d printed aluminum.
Martin calls this work a “true optimization from the atomic scale up to the component scale,” which has long been a dream of materials design. The study opens new frontiers in the use of aluminum alloys in 3d printing, and demonstrates the great potential of informatics in helping to unlock previously-intractable materials design problems.
- B Meredig, Chief Science Officer
· JH Martin et al., 3D printing of high-strength aluminium alloys, Nature (2017)