ELECTRICALLY ASSISTED DEFORMATION AND HEAT TREATMENT OF METALS

In recent years a novel metal manufacturing technique called Electrically Assisted Forming or Manufacturing (EAF/EAM) has been demonstrated to have the ability to enhance the forming limit of the material and, at the same time, to reduce the flow stress needed for the deformation, as well as the springback. The effects induced by the applied electrical current during the deformation are caused by the so-called Electroplastic Effect (EPE). Since its discovery, many researchers tried to explain how the EPE works, and some contrasting theories have also been developed. Conversely, to the electrically assisted forming, in which electrical current is applied during deformation, Electropulsing Treatment (EPT) is a new microstructure strengthening approach that uses high-density and short-duration electric current pulses applied to the bulk material. It has been observed that EPT was able to form an ultra-fined grain during phase transformation and recrystallisation, change orientation and texture, and influence the shape and distribution of secondary phase particles during solid-state transformation and solidification of metallic alloys. It has been reported that EPT could also heal microcracks within the material. The goal of my PhD research project is to contribute to the understanding of the physical metallurgy related to the effects of electric current applied to metallic materials, demonstrating its impact on formability and microstructural evolution during heat treatments. Research Objectives: • To understand how metallurgical phenomena such as recrystallization, recovery, and phase transformations are influenced by the presence of electric current, including pulsed current with very high peak current densities. • To gain a deeper understanding of the effects of continuous and pulsed current on the properties of the materials under study, and their ability to influence microstructural evolution during thermal treatments, particularly in alloys that are not yet widely explored. • To contribute to the study of the Electroplastic Effect (EPE) in multiphase alloys, such as duplex stainless steels. • To compare the results with those obtained from more conventional thermomechanical treatments, in order to assess the additional contribution of current application on material properties and workability, and to demonstrate the potential industrial advantages of this process, including the identification of an a-thermal effect. • Side activities include the investigation of the metallurgical-influenced corrosion of duplex stainless steels.