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Titanium and its alloys are difficult-to-form materials due to limited slip system and plastic anisotropy. Titanium is also prone to change in color due to oxidation at high temperatures. It is thus advisable to conduct deep drawing of titanium and its alloys at temperatures below 600°C. In this study, the drawability of Ti-6Al-4V sheet is evaluated in respect to the process parameters such as forming temperature, forming speed, and blank holding force at elevated temperatures. It is shown that the limit drawing ratio (LDR) increases with increasing temperature, but varies insignificantly with forming speed. The development of residual stresses in the wall of drawn cups during deformation was evaluated.

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Article history:Polydimethylsiloxane (PDMS) is a widely used material for replicating micro-structures because of its transparency, deformability, and easy fabrication. At the nanoscale, however, it is hard to fill a nanohole template with uncured PDMS. This paper introduces several simple methods by changing the surface energy of a nanohole template and PDMS elastomer for replicating 100nm-scale structures. In the case of template, pristine anodic aluminum oxide (AAO), hydrophobically treated AAO, and hydrophillically treated AAO are used. For the surface energy change of the PDMS elastomer, a hydrophilic additive and dilution solvent are added in the PDMS prepolymer. During the molding process, a simple casting method is used for all combinations of the treated template and modified PDMS. The nanostructured PDMS surface was investigated with a scanning electron microscope after the molding process for verification.