In the textbook "Fundamentals of materials science of superconductors based on Nb-Ti alloys . Application of superconductors" in the discipline "Fundamentals of material science of technical superconductors" features of the phase diagram of the Nb. system are considered Ti and superconducting properties of Nb. Ti superconductors. The main attention is paid to metallurgical problems of obtaining superconductors based on Nb-Ti alloys and factors determining their critical properties. Described the stages of manufacturing superconductors based on Nb-Ti alloys and the field of application of high-current and low-current superconductors. It is intended for students specializing in the field of physical materials science in the specialty "Physics of metals" .