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Equal channel angular pressing is one of the techniques in metal forming processes in which an ultra-large plastic strain is imposed on a bulk material in order to make ultra-fine grained and nanocrystalline metals and alloys. The technique is a viable forming procedure to extrude materials by use of specially designed channel dies without substantially changing the geometry by imposing severe plastic deformation. This technique has the potential for high strain rate superplasticity by effective grain refinement to the level of the submicronscale or nanoscale. We review recent work on new trends in equal channel angular pressing techniques and the manufacturing of die-sets used for the processing of metals and alloys. We also experimented on a copper alloy using the equal channel angular pressing technique to examine the microstructural, mechanical and hardness properties of the ultra-fine grained and nanocrystalline materials produced. After deformation, all samples were subjected to a hardness test and the results showed improved mechanical behaviour of the ultra-fine grained copper alloy that was developed. This research provides an opportunity to examine the significance of the equal channel angular pressing process for metals and alloys. That is, these ultra-fine grained materials can be used in the manufacturing of semi-finished products used in the power, aerospace, medical and automotive industries.

The very graphic name of 'sandwich composites' adequately describes them as structures with a relatively thick core made of lightweight or low density material separating two thin stiff and strong skins. Such choice of geometry and combination of materials yields a product with reasonable strength and bending stiffness in combination with lightness. This paper presents work in predicting the bending stiffness of a sandwich composite through its equivalent flexural rigidity by modelling the material in the geometry of a cantilever beam. The results are verified experimentally by obtaining, through the laser based optical NDE technique known as Electronic Speckle Pattern Interferometry (ESPI), the displacement curve of the cantilever beam subjected to a point load at its free end. A second experimental technique carried out involved monitoring the dynamic response of a cantilever beam in its first mode of natural vibration. The beam equipped with polyvinyldiene fluoride (PVDF) sensors yielded results which are compared to the values for the flexural stiffness obtained by the prediction and the experimental setup using ESPI.

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