The effects of dynamic strain aging (DSA) on residual stresses generated in Ni-base superalloys during heat treatments are not well understood. In this study, the residual stress field induced by water quenching an IN718 disc while undergoing DSA is studied using coupled thermo-mechanical finite element (FE) analyses in conjunction with neutron diffraction (ND) measurements. A visco-plastic constitutive model that incorporates the effect of DSA is proposed to describe the experimentally observed negative strain rate sensitivity and abnormal temperature dependence phenomena in the stress–strain response of solid solution treated IN718. The predicted quenching residual stresses in the disc agree well with the ND measurements. Due to the DSA, a propagating high plastic strain rate region can be identified in the disc during the early stages of the quenching process. Due to the negative strain rate sensitivity and abnormal temperature dependence effects caused by DSA, the predicted residual stresses are approximately 10% greater than when those two effects are not accounted for. The effects of different convection heat transfer conditions in the FE model are examined and discussed. It is found that the convection heat transfer coefficients have a great influence both on the disc residual stresses and DSA-related plastic strain rate field predictions.

To fully understand the impact of cyclic heating on the solid-state phase transformation behavior (SPTB) of multi-component multi-phase alloys (MCPA) during selective laser melting (SLM) and to provide possibilities for the precise customization of the material microstructure, a thermal-metallurgical coupling framework (TMCF) was developed. This framework integrates (1) an equivalent micro-zone heat source model and (2) a Johnson–Mehl–Avrami (JMA) phase transformation kinetic model. Using IN738 superalloy as an example, TMCF was effectively employed to predict the distribution and evolution of the γ′ phase during SLM. The results showed that the post-printing distribution of the γ′ phase is non-uniform, resulting from the interaction between the precipitation and dissolution behaviors occurring at varying temperatures across distinct spatial locations. Furthermore, the dependence of the γ′ phase on the SLM mode was quantitatively estimated. Specifically, the maximum volume fraction of the γ′ phase increased by a factor of 17.377, 60.780, and 5.214 when the laser power, scanning speed, and hatch spacing were modified by +50%, −25%, and −16.7%, respectively, within the process window. This finding can provide reference for the fabrication of additional MCPA. In this work, the thermal model within the TMCF was verified by the experimental data reported in the literature.