A new theoretical model for the low-temperature ignition process of magnesium particles is proposed. The model is based on physical-mechanical effects resulting from the buildup of oxide layers on the particle surface and their possible destruction as a result of mechanical stresses attributed to thermal and pressure expansion which are due to temperature elevation, melting and, in some instances, liberation of dissolved hydrogen and generation of magnesium vapors. The model attempts to describe and predict peculiar and unexplained phenomena, which have been observed experimentally during the low temperature ignition of magnesium particles, such as increase or pulsations in particle size, formation of hollow spheres, and fragmentation of particles