Amorphous metals as multi-talents in medical technology
Until now, implants and prostheses have mostly been made of steel or titanium. This has disadvantages: The materials do not adapt optimally to patients and their bones. They can break quickly, necessitating repeat operations. Recent research by Heraeus Amloy together with the University of Graz is on the verge of a breakthrough here: Thanks to amorphous metals, the ideal medical technology can be produced in the future using 3D printing or injection molding processes.
Nowadays, when a patient needs an implant, he or she has to make many compromises. There are only a few basic sizes, so improvisation is necessary in the case of injuries following accidents or tumors. The operating surgeon bends the spare parts of a piece of metal by hand and then fixes them to the bone with screws. However, this holds sometimes more and sometimes less well, because the metals are exposed to a real permanent load. Rib arches, for example, have to withstand around eight million breathing movements every year. It is therefore not uncommon for patients to suffer fatigue fractures because the materials are not elastic enough. A new operation becomes necessary. More durable and better alternatives do not yet exist.
About the project: Implants from the 3D printer
The Heraeus Amloy business unit wants to change that. Together with the University of Graz, the company is researching patient-specific implants and how they can be manufactured and used in close cooperation with clinics as part of the "Clinical Additive Manufacturing for Medical Applications" (CAMed) project. The focus is on the complete production process chain. The project partners are relying on additive manufacturing, 3D printing. 3D-manufactured amorphous implants are biocompatible and can be individually adapted to the patient's physique - an advantage particularly in the case of complex fractures. The process also saves material. This is because the laser only builds structures where they are needed.
The initial findings from the CAMed project are promising – additively manufactured implants with plus points for patients and hospitals are thus within reach. Other applications such as prostheses or heart valves are also conceivable.
Our contribution: amorphous metals for 3D printing and injection molding
However, for 3D printing to succeed, it needs a special material. This is where amorphous metals, also known as metallic glass, come into focus. In research, such metals have proven to be true all-rounders for medical technology. This is because they exhibit extraordinary properties: Because they are formed by shock-freezing metallic melts, the atoms have no way of forming a crystalline lattice and solidify in a disordered (amorphous) manner. This disordered internal structure makes the material corrosion-resistant, extremely strong and at the same time highly elastic. As a result, it can be used close to the bone as well as cut to size individually, and even thinner plates are stable. "Amorphous metals have a number of advantages over steel and titanium: This material combines the benefits of strength and elasticity. It adapts perfectly to the bone, promotes recovery and is also very well tolerated, as it can be implanted without cell deformation," says Valeska Melde, Head of Marketing & Sales at Heraeus Amloy.
Heraeus Amloy is currently developing new alloys for the production of implants. "As part of the CAMed project, we are currently testing the AMLOY-ZR02 alloy. Its main component is high-purity zirconium and it has already been certified as biocompatible," explains Jürgen Wachter, head of the Heraeus Amloy business unit. The company is the only manufacturer worldwide to offer two different process technologies: In addition to additive manufacturing, amorphous metals can also be processed by injection molding. The latter would be particularly suitable for mass production - of surgical screws or instruments, for example.