Scientific Events

Location: Max Planck Institute for Sustainable Materials

Sintering Fundamentals of Nano-Metallic Particle Interconnects

Sintered copper (Cu) nanoparticles have emerged as a promising substitute for sintered silver (Ag) nanoparticles in power electronics packaging, offering comparable electrical and thermal conductivities, superior mechanical strength, and lower cost. However, the complex interactions between microstructure evolution, interfacial bonding, and mechanical performance during sintering remain insufficiently understood. This research investigates the mechanical behavior, fracture mechanisms, and reliability of sintered Cu nanoparticles through a combination of microscale experiments and multiscale modeling. The studies revealed the anisotropic fracture toughness of sintered Cu nanoparticles, developed an Anand viscoplastic model to describe high-temperature deformation, and quantified interfacial strength while elucidating the effects of oxidation on bonding quality. Furthermore, the influence of particle morphology on mechanical properties was examined using micro-cantilever bending tests and phase-field fracture simulations. Overall, this work advances the understanding of sintered Cu nanoparticles and supports the development of reliable and cost-effective interconnect materials for next-generation power electronics. [more]

Ancient craft, new perspective: Recovery and recrystallization of deformed metal nanoparticles

Metallic nanoparticles are utilized in a growing number of applications due to their unique and tunable properties. However, one of the primary tools used to tune bulk metals properties, recrystallization, is yet to be used in the case of nanoparticles. We studied pristine, single crystal platinum nanoparticles during a recrystallization annealing after deformation. We found that deformation causes a dramatic change in particles orientation, while annealing induced a plethora of different particle behaviors. Microstructurally, nucleation of new grains was observed, but in the smallest particles these new grains were quickly absorbed back into the deformed matrix. We describe a phenomenological kinetic model to explain the strong correlation between the particle properties and their annealing behavior. [more]

It's all about transitions - dealing sustainably and reliably with critical metal oxides in simulations and technologies

Colloquia Series on Sustainable Metallurgy
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Towards a Sustainable Future: EU Safe and Sustainable by Design Framework and AI in Circular Economy

Colloquia Series on Sustainable Metallurgy
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Closing metal loops sustainably - opportunities & challenges for a successful circular economy

Colloquia Series on Sustainable Metallurgy
Metals are essential for climate and digital technologies, making resource-efficient use and high-quality recycling across their entire lifecycle crucial. This lecture explores the role of recycling in a true circular economy, highlighting the need for clear system definitions, realistic expectations, and coordinated processes to recover valuable materials sustainably and effectively. [more]

Mesoscale Modeling of Crystalline Materials: Decoding Microstructure Evolution

Comprehensive investigations of material properties in crystalline systems require information spanning atomistic to continuum scales. Mesoscale models play a crucial role in this context. They enable the study of large systems and long timescales while retaining microscopic details relevant to the targeted applications. This presentation illustrates recent results on key aspects of microstructure evolution in crystalline systems obtained via newly developed mesoscale frameworks for defects and interfaces. Using a bicrystallography-respecting continuum model that incorporates parameters obtained from atomistic methods, we first discuss phenomena associated with disconnection-mediated grain boundary (GB) motion, such as GB faceting and grain rotation. Then, through a phase-field formulation of this model, we demonstrate that internal stresses generated by disconnection flow (shear coupling) induce significant deviations from classical curvature-driven grain growth in microstructures. This provides a compelling explanation for the lack of correlation between GB velocity and curvature observed in recent experiments, identifying its primary cause. In the final section, an overview of other mesoscale frameworks that build upon the phase-field crystal model and its coarse-graining is provided. Representative results are presented, including the effects of temperature cycling on GB motion, as well as an emerging general framework for analyzing defect dynamics in systems with microscopic order, which extends beyond conventional crystals. [more]

Precision Epitaxy in Nanocrystalline Thin Films: Defect‑Tailored Platforms for Electrocatalysis

Topological defects—dislocations, grain boundaries, and related features—play an essential role in determining the properties of crystalline materials. When crystallite or functional domain sizes shrink to the nanometer scale, these defects become dominant. To date, however, neither bottom‑up nor top‑down synthesis has provided a reliable means of controlling them. Here, we demonstrate delicate control over shell epitaxy on nanocrystals within thin films, producing three‑dimensionally organized nanocrystallites with uniform grain boundaries and associated defects. In these structures, the resulting 3D‑patterned strain field can be mapped with atomic precision and tuned to introduce targeted dislocations or disclinations. Using multiscale crystallography and spectroscopy, we show that the uniformity and discreteness of these defects provide a clear correlation between local structure and collective electrochemical performance—specifically, catalytic activity in oxygen evolution and reduction reactions. Finally, we outline how this nanocrystallite‑engineering approach is guiding the design of next‑generation functional materials for energy nanotechnology [more]
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