Evaluation of local strain evolution from metallic whisker formation

The evolution of local strain on electrodeposited tin films upon aging has been monitored by digital image correlation (DIC) for the first time. Maps of principal strains adjacent to whisker locations were constructed by comparing pre- and post-growth scanning electron microscopy images. Results showed that the magnitude of the strain gradient plays an important role in whisker growth. DIC visualized the dynamic growth process in which the alteration of strain field has been identified as causing growth of subsequent whiskers.