Abstract 4

This study aims to get close to the tension-tension portion of the Forming Limit Curve (FLC) of 38 um thick CP Gr2 Titanium with the use of the bulge test. With the miniaturization trend of technology, the forming abilities of Ti have to be evaluated because it is well known that the formability changes when moving from macro to micro scale. The hydraulic bulge test creates pure biaxial tension by clamping a flat foil sample to obtain a fixed boundary condition and then applying pressure on one side to promote material deformation. In order to ensure that pure biaxial tension has taken place, the strain history will be recorded by taking measurements of the strain at specific pressure intervals from the start up to the burst pressure. If the strain history has equal major and minor strains, pure biaxial tension is confirmed. Strain is measured by studying the deformation of a grid of 50 um in diameter circles that are on top of the thin foil. This thesis tests four different bulge diameters of 20 mm, 15 mm, 10 mm, and 2 mm. When bulge diameter decreases, size affects are expected to increase. Theoretical calculations will be compared to LS-Dyna simulations and experimental results to check whether the theory continues to apply when moving to the smaller diameter thin foil. The wide range of diameters tested from 20 mm to 2 mm will allow for clarification of any trends when undergoing miniaturization in forming.