Microstructural evolution and performance improvement mechanism of Ti–6Al–4V fabricated by oscillating-wire laser additive manufacturing

This work proposes an oscillating wire laser additive manufacturing (O-WLAM), which is based on the wire laser additive manufacturing technology (WLAM) and combined with the laser oscillating welding technology. For different laser oscillation patterns, it shows a trend that metallurgical defects such as porosity, microstructural and columnar grain size decrease with the increase of oscillation frequency and oscillation amplitude. In solidified grains formed under laser oscillation, a complex oscillation of melt pool agitation could lead to a refining effect on the β grains size. The corresponding tendency of epitaxial growth of the prior β grains is weakened as well. The process experiments in this work provide a new idea of laser oscillation for wire laser additive manufacturing. The use of laser oscillation to achieve improvement of metallurgical defects and optimization of microstructure has some guiding significance for wire laser additive manufacturing.