Luleå tekniska universitet in Sweden
The goal is to identify the mechanisms governing the evolution for plastic response covering a wide range of temperature strain and strain rates. The ESR1 will have to study among other things: phases transformations, recrystallization and grain growth during hot deformation of Ti64 titanium alloy and 718 alloy.
The work requires basic thermo-mechanical characterisation, as literature data is scarce. ESR1 must be able to establish connections between the various material thermal and mechanical effects. He/she will calibrate the material parameters from observations of the microstructure and the overall response of high strain rate tensile tests, the Split-Hopkinson pressure bar test and the quick torsion test, in order to study the influence of different heat treatments and different hot deformations on the kinetics of the allotropic phase transformation. The ESR1 will have access to the advanced microstructural characterization equipment of the UBx, MAT, UPV-EHU and LTU laboratories to conduct accuracy characterizations (measuring bench, microscopy, EBSD, dilatometry, differential scanning calorimetry, gleeble ...).
In the light of these observations, a complete and accurate analysis of the material's structural evolution during the deformation process will help identify the different mechanisms involved according to the material studied (adiabatic shear bands, grain size, recrystallization, phases changes etc.).
The role of the ESR1 within the ENABLE project will be central. She/he will have to work in perfect coordination with the ESRs of the other work packages. ESR1 will propose constitutive models in high strains especially for ESR3 focused on dynamic recrystallization (DRX) and for ESR8 focused on friction stir welding (FSW). ESR1 will study the effect of the high strain rates for ESR7 specially the adiabatic shear bands formation which occurs during the machining. ESR1 will assist ESR9 in establishing a model for solidification of materials in the melt pool commonly observed in additive manufacturing (AM).
Finally, these experimental approaches will be the basis for the modelling work which will be carried out in close cooperation with ESR4 and ESR5 (WP2/Finite-Element). The experimental data obtained by ESR1 will constitute the calibration base for the microstructural modelling developed by ESR4.