Thermal Simulation Accuracy for Laser Cladding Fe313/Al via Dilution, Absorptivity & Heat Source Synergy

Aluminum alloys are widely employed in the aerospace industry owing to their lightweight characteristics. Laser cladding offers an effective means to enhance their surface hardness and wear resistance; however, its application is constrained by several inherent challenges: the high thermal conductivity and low laser absorptivity of aluminum substrates, coupled with the property mismatch between the substrate and cladding powder, readily induce stress concentrations and crack formation in the clad layer. High-fidelity temperature field simulation is therefore essential for predicting residual stresses and microstructural evolution. Conventional simulation approaches rely primarily on calibrating heat source parameters to match the molten pool morphology, yet they overlook the dynamic evolution of thermophysical properties arising from compositional variations in the dilution zone—a critical factor that compromises predictive accuracy. To address this limitation, this study proposes a two-step correction strategy that establishes a linkage between composition-dependent thermophysical properties and heat source modeling. In the first step, the target dilution ratio is used to inversely determine the elemental composition within the dilution zone, enabling the recalibration of thermophysical parameters in the melt pool region. This measure reduced temperature simulation deviations near the melt pool from 41% to 17%. In the second step, a sensitivity analysis of the temperature field to heat source parameters reveals that laser absorptivity predominantly governs the overall thermal distribution, whereas shape parameters primarily influence the central melt pool temperature. Accordingly, a sequential optimization of absorptivity and shape parameters was implemented. Collectively, this two-step approach reduced the average deviation between measured and simulated temperatures from 18.7% to 9.63%, and diminished molten pool geometry errors—width, length, and depth—from 42%, 48%, and 43% to 9.6%, 19%, and 6.6%, respectively. The results demonstrate that the synergistic optimization of material properties and heat source models substantially enhances the accuracy of temperature field simulations, offering a more reliable theoretical foundation for predicting clad layer performance in laser cladding processes.