Evidence of 3D strain gradients associated with tin whisker growth

Johan Hektor (1) , Jean-Baptiste Marijon (2) , Matti Ristinmaa (1) , Stephen Hall (1) , Håkan Hall (1) , Srinivasan Iyengar (1) , Jean-Sébastien Micha (3) , Odile Robach (4) , Fanny Benoit Grennerat (5) , Olivier Castelnau (2)

1 Skane University Hospital [Lund]
2 PIMM - Laboratoire Procédés et Ingénierie en Mécanique et Matériaux
3 SYMMES - SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé
4 NRS - Nanostructures et Rayonnement Synchrotron
5 Ministère de l'Éducation nationale

We have used Differential Aperture X-ray Microscopy (DAXM) to measure grain orientations and deviatoric elastic strains in 3D around a tin whisker. The results show strain gradients through the depth of the tin coating, revealing a higher strain deeper in the Sn layer. These higher strains are explained by the volume change occurring during growth of the intermetallic phase Cu6Sn5 at the interface between the Cu substrate and the Sn coating and at grain boundaries between Sn grains.

Mots clés: Whiskers; Intermetallic compounds; Lead-free solder X-ray diffraction

Domaines: Science des matériaux [cond-mat.mtrl-sci]

Johan Hektor, Jean-Baptiste Marijon, Matti Ristinmaa, Stephen Hall, Håkan Hall, et al.. Evidence of 3D strain gradients associated with tin whisker growth. Scripta Materialia, 2018, 144, pp.1-4. ⟨10.1016/j.scriptamat.2017.09.030⟩. ⟨hal-02007991⟩