  Ni-rich $\gamma$ cells and Nb-rich eutectic droplets that form during laser
power bed fusion solidification of Ni-Nb alloys are studied using experiments
and simulations. Finite element simulations estimate the cooling rates in the
melt pool and phase-field simulations predict the resulting cellular
microstructures. The cell and droplet spacings are determined as a function of
cooling rate and fit to a power law. The formation of Laves phase is predicted
for a critical composition of Nb in the liquid droplets. Finally, our
simulations demonstrate that anisotropy in the $\gamma$ orientation influences
the Laves fraction significantly.
