A numerical approach for predicting laser surface annealing process of Inconel 718 Original Research Article

Laser surface annealing (LSA) was performed on a 3-mm-thick plate to reduce the hydrogen embrittlement (HE) sensitivity of aged Inconel 718, and the applicable parameter ranges were obtained. A finite element method (FEM) program was developed to simulate the LSA processes. The laser absorption coefficients of the sample surface under different LSA conditions were deduced using the trial and error method. All LSA processes were simulated with the deduced laser absorption coefficients. Thermal cycling experiments were then used to prove that the dissolution kinetics of the γ″ phase in Inconel 718 follows the Avrami equation, the coefficients for which were further deduced. The relationship between the volume fraction of the γ″ phase and the alloy hardness was established based on the coherency strengthening mechanism of the γ″ phase. The hardness distributions and depths of the laser-annealed surface layers were calculated by applying all of the above results. The good agreement between the calculated and measured results demonstrated the feasibility of applying this approach to predictions of LSA processes.