Effects of laser modes on Nb segregation and Laves phase formation during laser additive manufacturing of nickel-based superalloy

Abstract Nb-bearing nickel-based superalloys were fabricated by laser additive manufacturing using both continuous-wave (CW) and quasi-continuous-wave (QCW) laser modes. Effects of laser modes on Nb segregation and Laves phase morphology were investigated. The responses to aging treatments of two different fabricated samples were also investigated. CW mode tends to develop columnar dendrites, relative severe Nb segregation and continuous distributed Laves phase, while QCW mode tends to produce fine equiaxed dendrites, less Nb segregations and fine discrete Laves phase. In addition, the QCW sample responses better to aging treatment than the CW sample.