Laser surface treatment of Ti6Al4V alloy: finite element analysis for predicting molten pool geometry and microstructure modifications

Abstract This study investigates the effects of laser surface treatment on Ti6Al4V titanium alloy using both experimental and finite element analysis. Experimental parameters included varying laser scanning speeds (30, 45, and 60 mm/s) while maintaining a fixed pulse frequency and average power. The temperature profiles during the treatment were monitored and used to calibrate the heat exchange coefficients in the numerical model. Metallographic analysis of the treated surfaces revealed increased hardness in the remelting zone while X-ray diffraction analysis confirmed the formation of the α’-phase martensite, particularly at lower scanning speeds. The 3D finite element model was calibrated against experimental data and effectively used to predict the molten pool geometry, including molten pool width and penetration depth. The numerical model accurately predicted the effects of laser treatment on microstructure and mechanical properties, offering a tool for optimizing laser surface treatment parameters for enhanced surface performance. The study demonstrates that laser scanning speed plays a critical role in controlling the molten pool dimensions and the resulting phase transformations, which can improve the alloy’s mechanical properties, including hardness and wear resistance.