Researchers from Melbourne’s RMIT University have developed a new titanium alloy that is nearly one-third cheaper to 3D print than standard Ti-6Al-4V.
The team outlined their methodology in a recent Nature Communications study titled “Compositional criteria to predict columnar to equiaxed transitions in metal additive manufacturing.”
This paper presents a time- and cost-effective approach to selecting alloying elements, aimed at optimizing metal additive manufacturing. It provides a framework for predicting the grain structure of 3D printed metallic alloys, allowing engineers to achieve performance improvements and cost savings.
Ryan Brooke, a PhD candidate at RMIT’s Centre for Additive Manufacturing (RCAM), led the initiative alongside Professor Mark Easton and Dr Dong Qiu. Brooke’s team is now exploring opportunities to commercialize its new metal 3D printing approach for aerospace and medical device applications.
RMIT’s novel alloy was not presented in the research paper for commercial reasons. It is reportedly 29% cheaper to 3D print than standard titanium. The new design framework also enables more even 3D printing and stronger final parts that possess enhanced ductility, according to the researchers.
“3D printing allows faster, less wasteful and more tailorable production yet we’re still relying on legacy alloys like Ti-6Al-4V that doesn’t allow full capitalisation of this potential,” Brooke explained.
“New types of titanium and other alloys will allow us to really push the boundaries of what’s possible with 3D printing and the framework for designing new alloys outlined in our study is a significant step in that direction.”
RMIT to commercialize new, low-cost titanium alloy
Brooke’s engineering team used their design framework to develop and 3D print samples of their new alloy at RMIT’s Advanced Manufacturing Precinct in Carlton, Victoria. They produced the parts using laser beam directed energy deposition (DED-LB).
In addition to cost savings, the process prevented the formation of column-shaped microstructures, flaws that can cause uneven mechanical properties in some 3D printed alloys.
Brooke has since accepted a Research Transformation Fellowship at RMIT to investigate the next steps for commercialization. RMIT has also filed a provisional patent to protect its design framework.
“By developing a more cost-effective formula that avoids this columnar microstructure, we have solved two key challenges preventing widespread adoption of 3D printing,” commented Brooke.
The study’s lead author, who holds a Master’s degree in Manufacturing Engineering, has conducted market validation through the Commonwealth Scientific and Industrial Research Organisation (CSIRO)’s ON Prime program. During the nine-week course, Brooke spoke with industry representatives across the aerospace, automotive, and MedTech industries to better understand their needs.
“What I heard loud and clear from end users was that to bring new alloys to market, the benefits have to not just be minor incremental steps but a full leap forward, and that’s what we have achieved here,” Brooke said. “We have been able to not only produce titanium alloys with a uniform grain structure, but with reduced costs, while also making it stronger and more ductile.”
Looking ahead, RMIT’s RCAM is actively pursuing new collaborations to advance the technology.
Professor Easton, Associate Deputy Vice Chancellor (Research Infrastructure), emphasized that the new alloy “requires a team from across the supply chain to make it successful.” He added that RCAM is seeking new partners “to provide guidance for the next stages of development.”
Researchers advance metal 3D printing
RMIT is not the only university working to improve metal additive manufacturing techniques. Earlier this year, a team from the University of Toronto developed a machine-learning-powered framework to accelerate and refine laser-based metal 3D printing.
The researchers’ system, called AIDED, allows users to predict and inversely determine optimal 3D printing parameters for DED-LB. This approach reportedly significantly reduces the time and experimentation needed to achieve high-quality results.
AIDED employs two trained machine learning models and a genetic algorithm to generate the best process parameters based on user-defined performance goals, such as print speed and melt pool geometry. According to the study, published in Additive Manufacturing, the framework achieved an R² score of 0.995 for predicting single-track melt pool areas. It also notched 0.969 for the tilt angle of multi-track melt pools, indicating impressive accuracy.
In other news, researchers from Cranfield University showed that controlling interpass temperature (IPT) in Cold Wire Gas Metal Arc (CW-GMA) welding can increase 3D printing productivity without sacrificing the mechanical performance of super duplex stainless steel (SDSS) parts.
Published in the Journal of Manufacturing Processes, the study evaluated the effects of three interpass temperature (IPT) settings (75 °C, 200 °C, and 350 °C) on the microstructure and properties of super duplex stainless steel (SDSS) during wire directed energy deposition. The researchers observed notable differences in thermal accumulation and grain coarsening, yet found minimal impact on phase balance or tensile strength.
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Featured image shows PhD candidate and study lead author Ryan Brooke inspecting a sample of the new titanium. Photo via Michael Quin, RMIT University.
