Thermomechanical modelling to optimise friction stir welding of Ti6Al4V Alloy validated by microstructural analysis

Prediction of temperature based on the process parameters in friction stir welding (FSW) of titanium alloys, particularly Ti6Al4V, underpins the production of defect-free welded joints at reduced levels of materials and energy wastages. This work proposes a new approach to model and validate the FSW process for Ti6Al4V based on the process variables using computational fluid dynamics (CFD). The work uses the sections welded by a newly developed low-cost single-use tool, to join 2-m long sections, to validate the model. The validation process was based on physical experimentation and microstructural measurements of micrographs produced using an Infinite Focus Microscope (IFM), which presented a simple technique when predicting thermomechanical parameters and properties including temperature distribution, torque, strain rate, and material flow properties. The developed model provides a predictive framework for a combined thermal and material flow response of Ti6Al4V under friction stir welding.