Interface controlled plasticity in metals: dispersion hardening and thin film deformation

Plastic deformation and strengthening of metals, a classic subject of physi cal metallurgy, is still a central theme of present-day materials research. This review focusses on two modern aspects of fundamental and practical in terest: the mechanism of dispersion hardening at high temperatures, which a llows the design of alloys operating close to their melting point; and the constraints on dislocation and diffusional deformation processes in metalli c thin films, a potential reliability problem for micro-systems subjected t o high internal stresses. The commonality lies in the importance of interfa cial effects: the interaction of lattice dislocations with interfaces - bet ween particle and matrix, or between film and substrate - controls the stre ngthening effect in both instances; diffusional creep occurs in both cases, but is again limited by interface effects. An attempt is made to summarize the current understanding of these phenomena with special emphasis on mode lling and transmission electron microscopy results. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.