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

• Deposition passes boost thermal accumulation (1866 °C to 2321 °C). • Substrate preheating at 300 °C reduces cooling rate by 32.5 %. • FSP reduces LMD residual stress by 70.7% via hybrid manufacturing. • Hybrid process forms ’bowl’ temperature and ’M’ stress patterns. • FSP refines grains by 90.6% via dynamic recrystallization. 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.