In the work, using the molecular dynamics method, the crystals of composition А3В are considered, for example Ni3Al and Pt3Al, for the possibility of excitation of soliton-type waves in them. To describe the interatomic interactions, the potentials obtained by the immersed atom method were used. It is shown that under a harmonic external action, excitation of soliton-type waves is possible in a Pt3Al crystal, but not in Ni3Al. The occurrence of such compression-extension waves is due to the excitation near the zone of action of discrete breathers with a soft type of nonlinearity, the existence of which is impossible in a Ni3Al crystal. The detected waves can propagate thousands of nanometers along a Pt3Al crystal without any loss of shape or speed. The shape of the received wave corresponds to the kink solution of the sin-Gordon equation. The total amount of energy carried by the wave is determined by the number of rows of atoms involved in the oscillations, we can talk about tens and hundreds of electron volts