Chalmers study improves AM processability of Ni-base superalloy
A doctoral student at Chalmers University of Technology, Gothenburg, Sweden, is addressing the challenge of additively manufacturing high-performance metals for use in extreme environments. In his paper, ‘PBF-LB of a non-weldable Ni-base superalloy CM247LC: Microstructure control, crack mitigation, heat treatment and creep performance,’ Ahmed Fardan Jabir Hussain explains that Ni-base superalloys are highly attractive for components in high temperatures applications, particularly within the aerospace and industrial gas turbine sectors.
Additive Manufacturing enables intricate designs, such as cooling channels inside turbine blades. These allow higher operating temperatures, which are critical for improving gas turbine efficiency. However, when it comes to high-performance metals, the manufacturing process is complex. One such metal is CM247LC, which is exceptionally durable and ideal for applications in extreme environments; however, it is also one of the hardest metals to process with AM.
“The superalloy is often called ‘the Holy Grail’ of metal Additive Manufacturing,” stated Fardan. “If we can process it successfully, it could enable higher operating temperatures and improve efficiency of industrial gas turbines.”
The alloy tends to crack either during manufacturing or in post-processing heat treatment and has limited resistance to deformation under long-term high temperatures (known as creep) compared with cast components, issues that make it unsuitable for industrial use in its current additively manufactured form.
Finding solutions through process optimisation
Rather than altering the alloy itself, Fardan focused on getting the most out of the existing standard composition. By fine-tuning laser power, scanning strategies, and heat treatments, he reduced cracking and significantly improved durability. These efforts resulted in nearly crack-free samples in simple geometries such as cubes. However, cracking during post-processing heat treatment remains an issue in more complex parts. Additionally, his research also indicates how to manufacture and heat treat CM247LC to improve creep performance.
Fardan added, “One of the biggest lessons through this work is that you can’t just fix one problem in isolation. If you reduce micro-cracking too much, you might worsen macro-cracking or creep performance. A holistic approach is essential. That’s where collaboration with industry really helps.”
Industrial benefits
Throughout his PhD, Fardan collaborated closely with Siemens Energy. Håkan Brodin, Materials Technology Expert at Siemens Energy, shared, “Fardan’s research has given us valuable insights into how to process these challenging materials. We’re already applying the learnings to develop new alloys and improve our additive manufacturing processes.”
“We’ve reached the limits with traditional materials and cooling strategies. To go further, we need better materials and processes, and this research helps us do exactly that,” Håkan Brodin continued.
Wider application
According to the Chalmers University of Technology, the ability to reliably manufacture high-temperature turbine components could transform energy production by enabling higher efficiency, reduced emissions, and more flexible supply chains. But the methods and insights from this research also have wider application.
“Even if this material in particular remains difficult, the lessons we’ve learned can definitely be applied to other superalloys and help advance additive manufacturing as a whole,” stated Fardan.
