EFFECTS OF GRAIN SIZE AND SPECIMEN THICKNESS ON MECHANICAL PROPERTIES OF POLYCRYSTALLINE COPPER AND COPPER-ALUMINUM ALLOY.

Abstract

The flow stress of both copper and Cu - 13 at%Al alloy decreases as the ratio of specimen thickness to grain size decreases below a critical value and is always satisfied in the thick specimens of Cu - 13 at%Al alloy. In thick copper, the grain size in the Hall-Petch relation is replaced by the mean free path of dislocations at various strains. It corresponds to the length of slip bands instead of the cell size.