The methods of resistance measurements, metallography and crystallographic X-ray analysis are used to study the changes in the phase composition and structure of alloys Pt50Ni50-xCux (x=0, 3, 5, 10, 15 and 25%) during annealing after plastic deformation. Annealing at temperatures below the Kurnakov point TK is found to cause ordering with retention of the original (fibrous) grain structure; new, recrystallized grains are formed as a result of annealing at a temperature above the TK. The mechanical properties of the alloys are determined after those treatments, and related to the structure.