Bandgap engineering in III-V ternary materials and nanostructures of different types (nanoislands, nanomembranes, vapor-liquid-solid (VLS) and catalyst-free nanowires (NWs)) requires precise compositional tuning by vapor fluxes. Here, we develop a fully self-consistent growth model for the vapor-solid and VLS pseudo-binary AxB1-xC nanomaterials and show that the vapor-solid distribution can be tuned from the equilibrium to kinetic Langmuir-McLean shape by decreasing the total (A+B)/C flux ratio. We demonstrate the excellent fits by the model of a wide range of available data for AlSbAs epilayers, InSbAs, InAsP and GaAsP NWs grown by different techniques under different total V/III flux ratios in vapor.