Due to its nature as a layer-by-layer production technique, the stresses and subsequent deformation from laser-based powder bed fusion are different from the ones observed in other manufacturing techniques. Additionally, because of the cyclic heating and cooling, the material undergoes significant microstructural changes during the process. Especially for the material Ti-6Al-4V, this microstructural change is pronounced, since the microstructure changes from β to α+β during the LPBF process. In this work, two models are coupled together in a novel way. First, a reduced-fidelity part-scale thermo-mechanical model will predict the stresses and deformation. This model uses both the meta-layer concept, and flash heating as methods for decreasing the computational cost. Secondly, a Johnson-Mehl-Avrami-Kolmogorov-based non-isothermal microstructural model is implemented as a state variable to estimate the change in phase fraction of the constituting phases. The results show that the part is made up mostly of a mix of α and α’ phases, and that the microstructural change only leads to a small change in the residual stress after the LPBF process.
|Journal||I O P Conference Series: Materials Science and Engineering|
|Number of pages||8|
|Publication status||Published - 2020|