Statistical and experimental study of effects of process parameters on Ti-6Al-4V coaxial wire-feed laser cladding

Three-beam wire-feed laser cladding, which generates a uniform energy distribution with a wire vertically fed into the molten pool, is a promising additive manufacturing technology. In this study, an experimental investigation and a statistical analysis of Ti-6Al-4V wire cladding using three-beam laser coaxial wire-feed cladding technology coupled with a 2 kW continuous fiber laser were carried out. The influences of the main parameters, including the laser power, wire feeding speed, and laser scanning speed, on the cladding geometry and process were investigated. The prediction models correlating the process parameters and clad geometry were developed via the response surface methodology (RSM). The models were checked using analysis of variance (ANOVA). Through optimization, the optimal parameters were achieved for the required clad with a width-to-height ratio of 5:1. A high-speed camera was used to investigate the cladding process under various process parameters. The laser power positively affected the widths of the molten pool and cladding layer. The molten pool and clad heights decreased with increases in laser power and scanning speed. Fine acicular martensite grains in the colony and basket-weave distributions were predominant in the cross-section of the cladding layer. The macrostructure investigation showed that the widths of columnar prior-β grains decreased with the increase in laser scanning speed.