Solution treatment followed by quench forming and annealing for the production of Ti-6Al-4V sheet metal parts (TISTRAQ)

The Institute I of FAU Erlangen-Nuremberg is working on the joint project TISTRAQ in cooperation with the project partners HEGGEMANN AG (HEG) and DYNAmore GmbH (DYN). The main objective of TISTRAQ is the development of a new quench forming process (TISTRAQ process) for the energy- and material-efficient production of Ti-6Al-4V sheet metal parts for aerospace applications. The sheet metal parts produced are expected to have improved mechanical properties compared to the initial state.

The TISTRAQ process can be divided into the following substeps: (a) resistive rapid heating of the sheet, (b) short-term solution treatment at about 20-80°C below the β-transus temperature, (c) simultaneous forming and quenching in the tool (STQ state), (d) downstream short-term annealing with air cooling (STA state). Due to the aspired very short overall process time of a few minutes, the formation of an oxygen-enriched brittle surface layer (α-case) is limited.

In order to be able to establish a new production process such as the TISTRAQ process, precise knowledge of the specific correlation between process parameters, microstructure and properties is essential. Gaining a fundamental understanding of the relevant influencing variables on the microstructure and mechanical properties of Ti-6Al-4V sheet material along the entire TISTRAQ process chain is therefore the overall objective of Institute I. Finally, an optimized thermomechanical process chain should be definable to make the best use of the material potential within the process.

The process related trials and investigations in resistive rapid heating and tool-bound qench forming are performed at HEGGEMANN AG. DYNAmore GmbH is developing a thermomechanically coupled simulation model that describes the material behavior and the forming process, taking into account the temperature- and time-dependent phase transformation kinetics.

The TISTRAQ project is funded by the Federal Ministry for Economic Affairs and Climate Action.