Diffusion-deformation multiphase field model applied to the growth of whiskers

The purpose of this project is to develop the theoretical framework, simulation models and experimental methods, in order to gain understanding of the active processes related to tin whisker formation and growth. Tin whiskers are hair-like single crystals that spontaneously grow out from tin-coated surfaces.

The exact mechanisms responsible for whisker formation and growth are not fully understood.

It is, believed that whiskers grow as a way to relax stresses, which mainly caused by the growth of the inter-metallic compound between the copper substrate and the tin layer.To improve the understanding of the growth process of the inter-metallic layer the following developments are necessary.

An experimental program which is able to track the evolution of phase transformation associated with the inter-metallic compound grow into the tin and copper regions.

Development of coupled diffusion-deformation phase field model which includes an accurate decription of the inter metallic phase transformation. When these developments are in place it is possible to consider 3D simulations of the whiskers growth.

The outcome of these simulations will be compared to the experimental observations made in aprevious project.The project will provide answers to the fundamental scientific questions of the nature of the mechanisms of whisker growth  that are still not completely understood today through unique results and insights on the driving force(s) behind whisker growth.