The dissolution of a titanium particle in aluminum under the conditions of the crystalline and amorphous state of aluminum and titanium was studied by the molecular dynamics method. It is shown that the state of the aluminum structure has little effect on the intensity of titanium dissolution. This is due to the formation around a crystalline titanium particle, regardless of the initial aluminum structure, of a crystalline layer of aluminum with a thickness of about 1 nm, which repeats the titanium lattice. This layer affects the mechanism and intensity of mutual diffusion near the Ti–Al interface. In the case of the amorphous state of the titanium particle and the aluminum matrix, the dissolution occurred several times faster than in the crystalline state of titanium. That is, the reduction in the ignition temperature of the reaction of high-temperature synthesis in the Ti–Al system is much more efficiently achieved not by amorphization of aluminum, but by amorphization of titanium.