Thermomechanical modelling for the linear friction welding process of Ni-based superalloy and verification

This paper presents a fully coupled thermomechanical model for the linear friction welding process of Inconel-718 nickel-based superalloy by using the finite element method. Friction heat, plastic work, and contact formulation were taken into account for two deformable plastic bodies oscillating relative to each other under large compressive force. The modelling results of the thermal history at the weldline interface and thermal field at a distance away from the rubbing surfaces were compared to instrumented data sourced from related publications for model verification. Optimal linear friction welding process parameters were identified via comparison of weld temperature to the liquidus temperature of Inconel-718 alloy. Comparison of interface temperature showed a consistent range of values above the solidus melting temperature (1250 celcius) and below the liquidus melting temperature (1360 celcius) of Inconel-718 alloy. For the first time, a visible linear friction welding process window is identified using a thermomechanical computational modelling method. Through computational modelling, the influence of welding process parameters on the heat transfer and deformation of weld was systematically investigated.