Under complex approach by means of simultaneous measurements (during the deformation) of stress-strain diagrams (τ-ε), the Hall coefficient R_H, electrical conductivity σ, temperature dependences of microhardness H_v(T) and quantitative analysis of interfacial interactions (energy of interfacial interaction γ_m and interfacial tension σ_m), the peculiarities of the mechanical properties in Cd_xHg_1-xTe solid-solution crystals (x = 0–0.26) with metal and semi-conductor properties are studied. The special role of point defects and the influence of band structure on the behaviour of mobile dislocations are established. As found, in the process of strain hardening, a significant contribution is made by the interphase interaction between neighbouring structural fragments inherent in the semi-metallic crystal as well as induced in the process of deformation. From the point of view of non-equilibrium thermodynamics, energy parameters of interphase interaction in a fragmented crystal are estimated and a mechanism of self-organization is proposed. The peculiarities of near-surface layers and their role in formation of the elastic-plastic state of the investigated crystals are analysed. As claimed, the crystal under process of deformation should be considered as an open non-equilibrium thermodynamic system that evolves to minimum entropy not only to preserve its integrity, but also to create new types of structures (defects) capable of more effectively dissipating the added energy.