Even the most advanced manufacturing fails if its foundation is weak. In the same way a bridge relies on reinforced joints for strength, advanced manufacturing depends on durable material meeting points to hold everything together.
Throughout his career, Zhengtao Gan has focused not on what advanced manufacturing technologies can already do, but on what they still struggle to achieve.
An assistant professor of manufacturing engineering in the School of Manufacturing Systems and Networks, part of the Ira A. Fulton Schools of Engineering at Arizona State University, Gan researches and develops the scientific foundations needed to make multi-metal additive manufacturing more reliable and practical.
By strengthening metal joints, this work can significantly improve systems such as rocket engines, biomedical devices and electronics.
“Gan is shifting the paradigm from trial-and-error fabrication to predictive, physics-informed design,” says Binil Starly, school director and professor in the School of Manufacturing Systems and Networks, part of the Fulton Schools.
The process combines two or more alloys within a single part. Heat-exposed regions use conductive materials like copper, while load-bearing areas are reinforced with stronger alloys. This targeted approach improves performance, reduces weight and extends the lifespan of critical systems.
“Multi-metal additive manufacturing is a new technology that will shape the whole field,” Gan says.
Gan received a National Science Foundation Faculty Early Career Development Program (CAREER) Award for his research on preventing interfacial cracks in multi-material parts. The CAREER Award supports early-career faculty who combine ambitious research with a strong commitment to education and provides approximately $550,000 over five years.
Powerful designs and persistent defects
While recent advances in artificial intelligence, or AI, and multi-material optimization make it possible to envision these complex structures in detail, turning those designs into physical parts remains a challenge.
“Multi-metal additive manufacturing and technologies like dissimilar metal welding all struggle with the same fundamental obstacle: cracks that propagate along the different materials’ interfaces,” Gan says.
Even small defects can affect performance in high-stakes applications such as aerospace or energy systems.
Heat, stress and microstructure
Interfacial cracking is difficult to tackle because it is driven by multiple processes, including thermal, mechanical and kinetic effects, that occur at the same time.
The material is heated to the point of melting, but different metals cool at different rates, creating temperature gradients and stress fluctuations that can cause materials to split. As they are fused together, their distinct properties may not align and create brittle weak points. Additionally, as atoms move unevenly across the surface, they can leave behind microscopic gaps that further weaken the material.
“All of these effects, thermal, mechanical and chemical, are coupled,” Gan says. “A comprehensive predictive model must capture them together to provide reliable guidance for crack-free manufacturing.”
Gan’s approach integrates multiple scientific frameworks into a single predictive model. Heat and mass transport models track how temperature and material composition evolve during printing, while crystal plasticity describes how the internal structure of metals, made up of many small grains, deforms under stress. Fracture mechanics determine when those stresses are high enough to cause cracks.
By combining these elements, the model can simulate how stresses build, how brittle phases form and whether the structure will fail.
“We will uniquely combine species transport with composition-dependent crystal plasticity,” Gan says. “Then we can validate the results with grain-level measurements across multi-metal parts.”
Using synchrotron X-ray imaging, Gan and collaborators can observe materials in real time as they are processed. These high-resolution techniques reveal how intermetallic layers grow and how cracks begin, providing experimental evidence that strengthens the model.
The result is a predictive framework that can guide decisions before a part is made. Engineers can choose material combinations and processing conditions that keep crack-driving forces below the material’s resistance, preventing failure rather than reacting to it.
From discovery to real-world use
Solving interfacial cracking could expand what multi-metal systems can achieve. In aerospace, combining copper’s thermal conductivity with steel’s strength enables rocket components that manage heat more efficiently without sacrificing durability. In energy systems, integrating conductive and magnetic materials can improve motor efficiency and thermal control.
“This research represents the kind of convergence ASU is uniquely positioned to lead, where advanced manufacturing, materials science and AI work together to solve foundational challenges,” Starly says.
Alongside this work, Gan is rethinking engineering education. He is developing a forensic learning approach where students analyze simulated manufacturing failures to identify root causes and apply core principles.
“The real breakthrough is being able to combine very different metals without cracking at the interface,” Gan says. “That will unlock design freedoms that next-generation aerospace, energy and biomedical systems have been waiting for.”
This CAREER Award project acknowledges support from the Advanced Manufacturing Initiative, or AMI, at the National Synchrotron Light Source II at Brookhaven National Laboratory, or BNL.
