Modelling of beam energy absorbed locally in conduction mode laser metal fusion

Fluid dynamics models for laser material processing with metal fusion in conduction mode generally assume a constant absorptivity. This parameter is known to govern the process. However, it used be pre-set by extrapolating absorptance measurements made at different conditions or adjusted reproduce experimental bead shapes. In this study new approach developed. It consists predicting as function of local surface conditions, including temperature. The proposed model applied alloy Ti-6Al-4V. found that changes temperature over wide range beam incidence angles. Thermo-fluid simulations tracking free-surface deformation are performed welding test cases Yb fibre and travel speeds. absorptivity coefficient commonly process clearly underestimates melt pool geometry predicted study. computational results also compared against good quantitative agreement depth, width, length, free contour geometry, curvature end depression left after re-solidification switch-off location obtained. show field depends on development stage, spatial within spot, conditions.