The ternary system Ni-Cu-Sn includes some phases with interesting mech
anical properties. The first group are the spinodal alloys in the 'Cu
corner', the second is a group of intermetallics with large lattice pa
rameters such as DO3, DO19 and 2H. The investigation of the pseudobina
ry phase diagram Ni2Cu-Ni2CuSn was undertaken to enable in future the
preparation of samples with controlled phase composition for further s
tudy of mechanical properties of such intermetallics and of related tw
o or, three phase composites. The solvus line and other boundaries wer
e revealed with the help of the so-called dynamical methods based on t
he measurements of physical quantities during controlled linear change
of temperature. The data are related to measurements after annealing
at various temperatures and also to determination of the structure aft
er cooling to room temperature. The main methods used were X-ray diffr
action (XRD) and analytical electron microscopy (AEM). The results are
related elsewhere to measurement of the electrical resistivity and to
the determination of solidus and liquidus temperatures by means of di
fferential thermal analysis (DTA).