In this work, systematic studies of thermoelastic martensitic transformations (TMTs) and atomic ordering, as well as magnetic phase transformations and properties of alloys of 4 quasi-binary systems based on Ni50Mn50- x Ti x ( x = 0…25), Ni50Mn50- y Al y ( y = 0…25), Ni50Mn50- z Ga z ( z = 0…25) and Ni50Mn50-αFeα (α = 0…25), Ni50-βMn50Feβ (β = 0…25) after heat treatment and deformation by high pressure torsion (HPT) were carried out. The methods of measurements of electrical resistance, microhardness, X-ray diffraction, transmission and scanning electron microscopy (TEM and SEM) were used. The temperatures of the TMTs, the phase composition and structure of the alloys, the structural types of thermoelastic martensite, the physical and mechanical properties, and the dependence on the chemical composition of all investigated alloys were established. The temperature-concentration regularities of the existence of these phases were determined. The critical temperatures of forward and reverse phase transitions in the alloys under study were measured by resistometry and magnetometry. It was found that doping with the third component (Ti, Al, Ga, or Fe) lowers the critical temperatures of the TMTs, shape memory effects (SMEs), and pseudoelasticity (PE) compared to the binary intermetallic NiMn. The phase diagrams were constructed. The purpose of this work is a comprehensive study of the crystal structure characteristics, phase transformations and properties of alloys based on the Ni-Mn system, binary and ternary quasi-binary doped Al, Ti, Ga, Fe, the construction of their phase diagrams.