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This study presents a comprehensive evaluation of the effects of multi-channel spiral twist extrusion (MCSTE) processing on the mechanical properties and structural evolution of AA5083. The structural evolution and texture developed were mapped by electron backscatter diffraction (EBSD) for three successive passes and compared with an as-annealed plate. An evaluation of the hardness and tensile properties was presented and correlated with the EBSD findings. The displayed EBSD results revealed that grain refinement was strongly associated with the presence of a high density of low-angle grain boundaries (LAGBs) after one pass, which developed into fine grains of less than 20 μm and high-angle grain boundaries (HAGBs) after three MCSTE passes. The three pass processing led to a 65% reduction in grain size. This reduction in grain size was coupled with an enhancement in the hardness and tensile properties. Additionally, the crystallographic texture study represented a slightly random texture due to the presence of intermetallic particles in AA5083. This study demonstrates the efficacy of MCSTE as a grain refinement tool.

Many of the petroleum-based materials and products are causing problems with sustainability of resources and disposal at the end of their lives. Such problems can be solved if biodegradable materials from renewable resources are used in product design. For a material to be fully biodegradable, all its constituents must be biodegradable and should come from renewable resources if it is to be sustainable. Starchplant fiber composites satisfy both conditions. In addition to their environmental benefits, materials from renewable resources can also be economically advantageous in certain applications, such as motorcar and packaging industries. This chapter starts with a review of the characteristics of biodegradable materials and uses case studies to illustrate their use in the design of sustainable products. The concept of design for a life (DFL), in which the material used in making a given product that will biodegrade at the end of its useful life, will also be explored.