Executive Summary : | Hexagonal Close Packed (HCP) materials like Magnesium alloys and Titanium alloys possess limited formability at room temperature because of the presence of less number of active slip systems. Conventionally these materials are deformed at high temperatures, which is called super plastic forming in which additional slip systems will be active [Samman et al. 2012]. Super plastic deformation temperature for magnesium is around 300 °C and for titanium alloys, it is around 900 °C. Forming at such a high temperatures demand for dies and tools made of special heat resistant materials, auxiliary equipment, additional space and additional cleaning processes to remove oxide layers [Leyens and Peters 2003]. This is restricting the usage of these high strength materials. One can alternatively make use of electro-plasticity principles in place of superplastic forming. It is envisioned that applying high current short duration electric pulses during the deformation can stimulate the dislocation motion increasing the formability of the material. This phenomenon is demonstrated in incremental sheet forming in the earlier work of the principal investigator [Asgar 2014]. The surface temperature while forming Ti6Al4V using 140 A current was around 180 °C, which confirms that the material did not undergo super plastic deformation. However, there are claims that the local temperature inside the material might have reached super plastic temperature. It is very important to know the deformation mechanism in electric assisted forming because it effects the mechanical and metallurgical properties of the material. In the present work, microstructural investigation of magnesium and titanium alloys formed using electric assistance is planned to understand the deformation mechanism and microstructure evolution. 1. T.A. Samman, K.D. Molodov, D.A. Molodov, G. Gottstein, S. Suwas (2012), Softening and dynamic recrystallization in magnesium single crystals during c-axis compression, Acta Materialia, 60(2): 537-545 2. C. Leyens and M. Peters (2003), Titanium and Titanium Alloys: Fundamentals and Applicatons, Weinheim: WILEY-VCH Verlag GmbH & Co. KGaA, 279-283 3. J. AsgarR. Lingam and V. N. Reddy (2014), Tool path influence on electric pulse aided deformation during incremental sheet metal forming, International Conference and Workshop on Numerical Simulation of 3D Sheet Metal Forming Processes (NUMISHEET 2014) |