Abstract
The effect of diffusion-annealing on mechanical properties was studied by tensile test on the aluminum polycrystals coated with 1.5μ thick silver- and copper-evaporated films.
The results obtained are summarized as follows.
(1) As-coated specimens with evaporated silver and copper films only show a slight increase in strength, while marked increases in both yield and flow stresses are achieved when diffusion-annealed at 450550°C for 148 hr.
(2) As the annealing temperature becomes higher, the lower maximum strength is revealed at the shorter diffusion annealing time.
(3) More pronounced effect of diffusion-annealing is observed in the specimens coated with copper than those with silver.
(4) Such surface strengthening by diffusion-annealing is related to the formation of intermetallic com-pounds which occured by the diffusion of the film into the substrate.
