In this paper, flame propagation through heterogeneous hybrid aluminum-boron dust cloud including the effect of particle Poly-dispersion was simulated. Particles were distributed randomly within a three-dimensional domain. A discrete thermal model based on heat transfer between distinct metallic particles was developed to estimate flame propagation speed in the mixture. The flame propagation speed of the hybrid dust cloud in air was calculated for a range of total particle concentrations and different aluminum and boron partial concentrations. The presented results showed that the flame front velocity increases as the weight percentage of aluminum particles increase. In addition, adding aluminum to boron dust cloud can improve the flame propagation speed. To investigate the roles of conduction and radiation as well as radiative heat loss, time variations of particle temperatures when only one of the heat transfer mechanisms is present were evaluated and discussed. Careful examination of the numerical results showed that conduction heat transfer had the dominant role in aluminum and boron aero-suspension combustion.