Thermomechanical behavior of Ti-6Al-4V alloy via hybrid manufacturing with laser metal deposition and friction stir processing

This study investigates the hybrid manufacturing process combining laser metal deposition (LMD) and friction stir processing (FSP). To numerically simulate this hybrid process, a thermo-mechanical coupled model for additive and equivalent manufacturing of Ti-6Al-4V alloy was developed using ABAQUS software. The model reveals the evolution of temperature and stress fields and their influence on microstructure regulation. Results indicate that the layer-by-layer deposition in LMD causes the molten pool temperature to rise incrementally from 1866 °C in the first pass to 2321 °C in the 20th pass. Preheating the substrate to 300 °C reduces the cooling rate by 32.5 % (from 1203.12 °C/s to 812.41 °C/s) and promotes a 9.4 % increase in grain coarsening within the deposited layer. As-deposited components exhibit a stress distribution characterized by tensile stress at the center and compressive stress at the edges, with an average equivalent stress of 650.25 MPa. The FSP process generates a bowl-shaped temperature field of 1380.15 °C in the stirred region, inducing dynamic recrystallization that refines grains by 90.6 % and redistributes stresses to form an “M”-shaped residual stress field (average equivalent stress 251.03 MPa). This model successfully quantifies the thermo-mechanical behavior of the entire hybrid manufacturing process, providing a theoretical foundation for collaborative multi-process regulation of microstructure and properties.