Grain Boundary Sliding

In this paper, the mechanical behavior of freestanding thin sputter-deposited films of Au is studied at temperatures up to 340°C using tensile testing. Films tested at elevated temperatures exhibit a significant decrease in flow stress and stiffness. Furthermore the flow stress decreases with decreasing film thickness, contravening the usual notion that “smaller is stronger”. This behavior is attributed mainly to diffusion-facilitated grain boundary sliding.

This paper has been accepted by Scripta Materialia.

It is commonly assumed that grain boundary sliding can control plastic deformation in fine grained crystalline solids.  Superplasticity is often considered to be controlled by grain boundary sliding, for example.  I have never accepted that view, though my own opinion is very much at odds with the commonly accepted picture.  When I was asked to write a paper in honor of Professor F.R.N. Nabarro's 90th birthday (Prof.