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Description of the thermo-mechanical properties of a Sn-based solder alloy by a unified viscoplastic material model for finite element calculations

: Kabakchiev, Alexander; Metais, B.; Ratchev, Roumen; Guyenot, Michael; Buhl, P.; Hossfeld, M.; Metasch, René; Röllig, Mike


Institute of Electrical and Electronics Engineers -IEEE-:
15th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems, EuroSimE 2014 : 7-9 April 2014, Ghent , Belgium
Piscataway, NJ: IEEE, 2014
ISBN: 978-1-4799-4791-1 (Print)
ISBN: 978-1-4799-4790-4
International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) <15, 2014, Ghent>
Conference Paper
Fraunhofer IKTS ()

Automotive electronic devices are exposed to substantially harsher thermo-mechanical loads compared to commercial consumer electronic products. As a consequence, solder joints carrying out the electrical interconnection between the components undergo deformation and degradation under thermal cycling, which can determine the lifetime of the electronic assembly in long term operation. In the past decade, lifetime prediction methods for solder joints based on finite element (FE) simulations are increasingly employed in the process of product design. However, constitutive FE models for solder alloys capable of describing their mechanical behavior at the relevant conditions of automotive applications are still not widely established. Here, we employ a unified viscoplastic material model initially proposed by Chaboche et al. in order to address the mechanical properties of an as-casted Sn-based solder alloy under a cyclic mechanical load. Extensive experimental investigations at temperatures from -40°C up to +150°C reveal a complex nonlinear interplay between hardening, recovery and thermally activated inelastic deformation processes in the material studied. We identified the necessary constitutive model terms and performed parameter calibration according to their specific functionality. A very good agreement between the numerical calculations and experimental data is achieved, which renders the constitutive model used a very promising approach for a wide use in FE simulations of lead-free solder alloys.