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Investigations of the easy glide region in single crystals of well-known f.c.c. Cu alloys between 85 and 400 OK are reported. From careful measurements of the strain rate dependence of the flow stress and from microscopic observations (static and cinematographic) of the development of the glide bands i t is concluded that the "active slip volume" [l] of these crystals depends on strain rate and temperature. A detailed analysis of the results yields values for the number, the activation energy, and the activation volume of the obstacles responsible for the thermally activated process. We suggest that the obstacles are statistically distributed clusters of the atoms alloyed to copper.

Lamination parameter optimisation is a highly efficient type of composite optimisation. An equally efficient transformation of lamination parameters into stacking sequences is not yet available. This paper presents a general method for rapidly transforming lamination parameters into continuous stacking sequences. Systematic studies of the relationship between lamination parameters and stacking sequences provide a broad understanding of the transformation problem. An important finding is that multiple stacking sequences share the same lamination parameter set. The transformation is therefore not unique and has to account for multiple layup solutions. The layup retrieval algorithm uses primitive optimisation techniques to search for all optima in the layup space. Admissible ply angles and layer numbers are hereby not restricted. In two representative examples, the authors show the algorithm's capabilities of finding all stacking sequence solutions of a twelve layer laminate and of finding multiple stacking sequence solutions for arbitrary layer numbers. This makes the algorithm applicable for stacking sequence retrieval, the last step in lamination parameter optimisation.

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