Numerical simulation of thermal-mechanical development of GH4169 alloy in laser additive manufacturing process

In order to solve the problem of deformation and even cracking in the laser additive manufacturing process of GH4169 alloy, a direct coupled thermo-elastoplastic finite element method was used to simulate and analyze the temperature and stress evolution during the laser additive manufacturing process of GH4169 alloy single-layer multilayer wall. The results showed that the deposition specimen underwent rapid heating and cooling during the laser additive process, and the temperature change rate exceeded 1×10~⁵℃/s. The peak temperature of the thermal cycle exceeded 2 500 ℃, and the highest temperature reached 2 876 ℃．The area scanned by laser deposition was constrained by the cooling shrinkage, which resulted in high stress. The temperature of the area scanned by the laser during the subsequent deposition increased again,which would first release the stress formed by the previous deposition, then would cause greater stress as the temperature decreased. At the moment when the deposition was over, the temperature of the part abnormally increased where the deposited layer was connected to the substrate.The residual stress of the deposition layer was dominated by tensile stress, up to 875 MPa. The stress component along the deposition direction was the largest. The residual stress of the substrate near the junction with the deposited layer reached about 800 MPa, and the residual compressive stress was distributed in the distance.