The 573 K and 773 K isothermal sections of the phase diagram of the Pr–Ni–Ti ternary system

The 573 K and 773 K isothermal sections of the phase diagram of the Pr–Ni–Ti ternary system were investigated by X-ray diffraction, differential thermal analysis, optical microscopy and electron microscopy techniques. The 573 K isothermal section was restricted to the Pr-rich and Ti-rich parts of the Pr–Ni–Ti ternary system. The 773 K isothermal section was restricted to the Ni-rich part of the Pr–Ni–Ti ternary system. The (partial) 573 K isothermal section consists of 6 single-phase regions, 9 two-phase regions, and 4 three-phase regions. The (partial) 773 K isothermal section consists of 9 single-phase regions, 15 two-phase regions and 7 three-phase regions. The maximum solid solubilities of Ti in PrNi 2, PrNi 3, Pr 2Ni 7, PrNi 5, and Ni are about 2.5 at.% Ti, 1.5 at.% Ti, 1.0 at.% Ti, 2.0 at.% Ti, and 7.5 at.% Ti at 773 K, respectively. The solid solubilities of the other single-phase regions were too small to observe. The existence of any ternary compounds was not observed in the two partial ternary isothermal sections. The decomposition of NiTi was not observed in the Ni–Ti binary system or in the Pr–Ni–Ti ternary system.