Thermomechanically Coupled Modeling and Process-Parameter Analysis of Laser-Field-Assisted Hybrid Milling of GH4096 Superalloy

Abstract

GH4096 is a Chinese nickel-based disk superalloy used for disks and shafts in advanced gas-turbine engines, where creep, fatigue, corrosion resistance, and microstructural stability are service-critical. These requirements are associated with high deformation resistance and thermomechanical loading during milling. However, laser-assisted milling (LAM) of GH4096 has not yet been systematically investigated. This study addresses that material–process gap through a three-dimensional thermomechanically coupled finite-element analysis based on a GH4096 constitutive-damage description. Johnson–Cook (JC) plasticity and damage parameters are calibrated using quasi-static, high-strain-rate, elevated-temperature, and stress-state-dependent data, while displacement-based damage evolution is used after damage initiation. A moving Gaussian surface heat source reproduces localized preheating and coupled material removal. The model quantifies the effects of laser power, spot radius, cutting depth, feed speed, and spindle speed on milling force, the transient temperature field and surface von Mises equivalent stress. Intermittent force peaks occur in all three directions, with the largest local peaks arising mainly from axial RF3 loading. Feed speed produces the largest peak-force variation relative to the baseline case (73.0%), followed by cutting depth (65.6%). Laser power, spot radius, and spindle speed produce variations of 29.7%, 28.8%, and 28.2%, respectively. Force peaks respond non-monotonically to laser power, spot radius, and spindle speed. Maximum surface von Mises equivalent stress also varies non-monotonically with all five parameters. Feed speed produces the largest fluctuation, peaking at 623.56 MPa at 20 mm/s before decreasing to 529.32 MPa at 30 mm/s. Cutting depth yields a minimum of 502.88 MPa at 0.5 mm and a maximum of 580.90 MPa at 0.9 mm. Surface von Mises equivalent stress peaks at 619.75 MPa at 400 W and decreases to 550.89 MPa at a 2.2 mm spot radius. It increases sharply at 2.4–2.6 mm and reaches 573.14 MPa at 10,000 r/min before declining. These results establish a bounded basis for coordinating optical and mechanical parameters in GH4096 LAM within the investigated model and parameter ranges.