Aside from the exerted stress created from the indentation of load, it can be deduced as the existence of the copper-based substrate can also performed as the pioneer of the formation of pure tin. Both samples of different weight are stored simultaneously in the same ambient temperature under different storage period.
Based on the current studies, the creation of pure tin whisker include the grain boundary sliding motion which start with the critical pressure about -15 MPa 32. Eventually, the stress gradient is created to drive out the pure tin atoms from the surrounding undeformed areas to the base of hillock and push up the hillock outwards.
