CAREER: Process-Induced Interfacial Crack Formation in Multi-Metal Additive Manufacturing

About This Grant

Multi-metal additive manufacturing enables the creation of multi-metal architectures that exceed the intrinsic property limits of single alloys by spatially combining complementary materials within a single component. Such capability is critical for next-generation aerospace systems, energy technologies, biomedical devices, and national defense applications. Despite its promise, the widespread use of multi-metal additive manufacturing is limited by cracking at dissimilar-metal interfaces, which undermines reliability and discourages industrial adoption. This Faculty Early Career Development Program (CAREER) project addresses this fundamental challenge by developing a science-based understanding of how and why interfacial cracks form during processing and how they can be avoided. By enabling defect-free multi-metal components, the project supports U.S. competitiveness in advanced manufacturing while contributing to workforce development. Integrated research, education, and outreach activities engage K–12 students, undergraduates, and graduate researchers through hands-on design-to-manufacture challenges and a new forensic learning framework that emphasizes evidence-based reasoning, creativity, and critical thinking. The research objective is to develop a rigorously validated multi-physics framework that predicts process-induced interfacial cracking in multi-metal additive manufacturing. The project integrates multicomponent heat and mass transport, grain-scale crystal plasticity, and coupled fracture mechanics to capture the interactions among residual stress evolution, liquid-metal embrittlement with Kirkendall porosity, and brittle intermetallic layer formation. Two representative alloy systems, Cu-10Sn/904L stainless steel and Ti-6Al-4V/AlSi10Mg, are studied to isolate distinct cracking mechanisms and validate the framework across different metallurgical regimes. Model predictions are validated using in-operando synchrotron X-ray imaging and diffraction and high-resolution electron backscatter diffraction, with an industrial testbed for fabricating a next-generation multi-metal rocket engine. The resulting theory and computational tools are expected to provide quantitative guidance for selecting process parameters and material combinations that suppress crack initiation by maintaining the local crack-driving force below the evolving interfacial fracture resistance. The outcomes are expected to extend beyond additive manufacturing to inform dissimilar-metal joining technologies and the design of robust, multifunctional engineered systems. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.