Sintering densification behaviors and microstructural evolvement of W-Cu-Ni composite fabricated by selective laser sintering

The sintering densification behavior and microstructural evolvement of W-Cu-Ni alloys (90 wt% W, 5 wt% Cu, 5 wt% Ni) were investigated via selective laser sintering (SLS). Through the analysis of the surface morphology and microstructure obtained by different laser sintering parameters, revealing that the sintering mechanism evolves from solid state sintering to liquid phase sintering depends on the laser input energy. The sintered density initially increases with the laser input energy then decreases; the poring and balling phenomenon cannot be eliminated drastically. The SLS of W-5Cu-5Ni (wt%) alloys is a complete process of molten liquid phase spreading and solidifying, which is determined by the intrinsic properties of W/Cu and the laser sintering parameters. Setting a moderate temperature for the molten pool would restrain the phenomenon of balling and poring, so as to achieve a sintered sample which is nearly densified. Combined with composition and phase analysis, Ni-Cu is acting as the binder phase, adding Ni additive promotes partially dissolution of W, meanwhile most nonmelting W is acting as structural phase.