Programme de recherche
(Anglais)
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COST-Action MP0602 - Advanced Solder Materials for High Temperature Application- their nature, design, process and control in a multiscale domain
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Description succincte
(Anglais)
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Multi-scale modelling of the durability of lead-free solder joints in high-temperature, highperformance applications including the mechanisms of Inter Metallic Compounds interfacial failure, micro-structural changes and visco-plastic damage accumulation.
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Partenaires et organisations internationales
(Anglais)
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AT, BE, BG, CH, CZ, DE, DK, FI, FR, HU, IE, IT, NL, PL, PT, RO, RS, SE, SI, SK, TR, UK
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Résumé des résultats (Abstract)
(Anglais)
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The main goal of this project was to develop the methodology and tools for the multi-scale modeling of the durability of lead-free solder joints in high-temperature and high-performance applications. The first part of the research aimed at developing macroscopic models of the interfacial fracture behavior of solder joints with a focus on rate dependent effects. The second part of the work focused on the development of high fidelity multiscale numerical simulation models in order to predict the change in macroscopic response of solder joints caused by the evolution in their microstructures. The main outcomes of the project are: 1. Experimental characterization of visco-plastic behavior and failure mechanisms in lead-free solder joints by shear testing and performing stable fracture tests at different loading rates: The results indicated that increasing testing strain rate can significantly increase the tendency for developing an interfacial failure and reduce the maximum load capability of the joints. 2. Cohesive zone finite element modeling of interfacial crack propagation in lead-free solder joints: the results confirmed that the main energy dissipation mechanism in the solder joint at low loading rate is due to the viscoplastic deformation of bulk solder, while, when increasing the rate, the portion of energy dissipated due to interfacial damage increases. Employing the model developed, the mutual effect of the viscoplastic behavior of the bulk solder and the interfacial damage progression was clarified. 3. Three-dimensional (3D) characterization of intermetallics evolutions in lead-free solders due to thermal-ageing: the evolutions in the configurations and sizes of Ag3Sn and Cu6Sn5 intermetallic particles distributed in near-eutectic SnAgCu solder have been investigated by 3D scanning of microstructures in the solder after various ageing intervals and at different temperature by employing synchrotron X-ray tomography and focused ion beam-scanning electron microscopy (FIB-SEM) techniques. The results indicate a remarkable coarsening especially in Cu6Sn5 intermetallics and were used as input for FE homogenization model. 4. Microstructural-based homogenization modeling of ageing effects on the plastic deformation behavior of eutectic mixture of SnAgCu solder: The representative volume element size and constitutive behaviors of the eutectic mixture in as-soldered and aged conditions are determined by a feature-preserving numerical homogenization procedure. The homogenization results clarified the correlation between the microstructural evolution of solders and the change in their mechanical behavior during thermal ageing. The homogenization results were validated experimentally through nanoindentation tests and theoretically using the dislocation detachment theory. Both the experimental and theoretical results have shown a good agreement with homogenization simulations.
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