Paderborn University
The steel alloy being printed at Paderborn University
The United States might be one step closer to its goal of having half of all new vehicles sold in 2030 be zero-emissions electric vehicles. A pair of undergraduates from the Massachusetts of Technology (MIT) and their graduate student coach in Germany have developed a new type of steel not for a cars’ build, but for die-casting moulds that stamp them out in a few discrete parts.
MIT junior Ian Chen and 2022 graduate Kyle Markland placed third in ASM Materials Education Foundation’s 2022 Undergraduate Design Competition. The 3D printable steel alloy that earned them the place was inspired by an innovative manufacturing approach called Giga-casting, popularised by Tesla and used to assemble the all-electric Model Y.
Chen accepted the award at a ceremony in New Orleans on September 12, and him and Markland will share the 1,000 USD prize money. ASM Materials Education Foundation is the charitable division of materials engineering organisation ASM International. Its aim is to promote applied science careers to students and teachers.
Chen and Markland’s project has its roots in their Computational Materials Design class, taught by Gregory Olson, the Thermo-Calc Professor of the Practice at MIT. Olson is a leading scholar in computational materials science, which uses computer modelling and simulation to understand and design new materials. His methodology has been used by Apple to create the Apple Watch, and even caught the attention of Tesla CEO Elon Musk according to Olson.
“To get affordable electrical cars with good range, he [Musk] had to make aluminium structures affordable,” said Olson. “So he looked at the kind of die casting for little car models and said, ‘why not scale it up? We’ll cast the whole car’”
Tesla used Olson’s computational approach for the aluminium that could be die cast. Cars are typically built using hundreds of die-cast parts, that are later put together on an automated assembly line to make a vehicle. The Giga-casting process, named for the massive casting machines known as Giga Press, instead involves casting just two or three large automobile pieces, reducing the complexity of the process and the costs.
Charles Kuehmann, Vice President of Materials Engineering at SpaceX and Tesla, and a past student of Olson’s, stated the need for a better die steel, also called tool steel, that would be printable. He confirmed the need for a material that could be loaded into a 3D printer to print new dies with better strength and thermal properties.
Speaking about conventional steels, Olson said they are: “Quite brittle and cracking-prone if you try to print them.”
Olson turned to Florian Hengsbach, a visiting student at MIT from Paderborn University who had returned to Germany during the pandemic in 2020, to help the students as an advisor.
“Here at Paderborn, we print materials, characterise them down to the atomic level, and determine the process-microstructure-performance correlation,” Hengsbach said.
Hengsbach began working in Europe, with Chen and Markland working at MIT in Cambridge, Massachusetts, the team began designing the new metal using CALPHAD, a method for calculating the properties of materials. Through the use of thermodynamic material models, the team could predict what new materials would do in different conditions.
Ian Chen and Kyle Markland
Ian Chen (left), Kyle Markland (right)
Hengsbach formulated the material at Paderborn’s additive manufacturing centre and printed it as a test, making the new metal alloy, melting it, then atomising it into small droplets that solidify, making a powder. The powder is layered and melted by laser into an object in a 3D printer.
The team stated the possibility of also using the material elsewhere in manufacturing, such as injection moulding, or press hardening, which can form high-strength steel in complex shapes. Hengsbach claimed that it could be used ‘everywhere you want to use conformal cooling channels’.
A U.S. patent application was filed for the new printable die steel, and the next step is testing in casting die applications. The team has begun talks with Tesla.
“This project has pushed me toward a more computationally driven materials area,” said Chen. “Where computational models are used as a critical tool for materials design and analysis.”
Markland graduated in May of this year with a Bachelor of Science degree in materials science and engineering. He recently started working full time at the Ford Motor Company in Dearborn, Michigan. Part of the Ford College Graduate programme, he will work on different projects in his first two years, beginning with vehicle paint engineering and corrosion prevention.
“It feels great to have our work recognised by ASM,” Markland said. “Sometimes classwork can feel abstract or removed from the real world, and it’s a refreshing reminder that the project we did has recognition beyond just a class assignment.”
MIT has seen multiple 3D printing developments in recent months. Researchers at the institution recently created a programmable 3D printed material that can sense its own movements, a team also developed a process that uses artificial intelligence to correct 3D printing errors in real time, and another team created 3D printed sensors for satellites that determine the chemical composition and ion energy distribution of the atmosphere.
