Ni77Ga23 alloys were undercooled and rapidly solidified using glass fluxing treatment. An in situ diagnosis of dendrite growth velocity during rapid solidification processing suggests crystallization of a disordered solid solution from low to high undercoolings. While this diagnosis is consistent with an X-ray diffraction analysis, a neutron diffraction analysis suggests the formation of Ni3Ga phase in addition to the disordered solid solution. An EBSD analysis shows the formation of an equiaxed microstructure at a high undercooling. A HAADF-STEM study of equiaxed grains reveals a superalloy-like substructure, where cuboidal coherent precipitates of Ni3Ga phase are dispersed in the matrix of the disordered solid solution. A HRTEM study further reveals disordered nanodomains in the lattice of Ni3Ga phase. It is concluded that rapid solidification processing can lead to facile formation of a superalloy-like microstructure without an aging treatment.