Surface and Microstructure Considerations in High Speed Single Point Incremental Forming of Ti6Al4V Sheets

Flexible sheet metal forming processes represent a big challenge, which have involved a number of researchers all over the world in the last decades. Among these, Incremental Sheet Forming (ISF) process is one of the most investigated and promising due to its simplicity, cheapness and applicability. Furthermore, the possibility to increase the process velocity makes ISF more suitable than in the past; as a consequence, its application potential is surely increased. It was already highlighted that high speed significantly raises the process temperature, improving the workability of Titanium alloys. In this process configuration, no further heating source is strictly required because the temperature increase is generated due to the plastic deformation and the friction conditions at the interface between punch and sheet. While the process feasibility has been already investigated, a lack of knowledge in the literature is present focusing on the analysis of the process impact on the material properties. Accordingly, an experimental campaign on Ti6Al4V sheets has been performed, considering a punch speed two orders of magnitude higher than the conventional one. The obtained surfaces have been compared to sheets worked by traditional velocity to accurately analyze the impact of high speed. Furthermore, microstructural analyses have been carried out confirming the high speed suitability. All the details are reported in the manuscript.