Liquid-Solid Phase Equilibria of Nb-Si-Ti Ternary Alloys

To determine the liquid–solid phase equilibria of the Nb-Si-Ti ternary system, Nb-Si-Ti alloys of different compositions are prepared. By means of scanning electron microscopy (SEM), X-ray diffraction (XRD) and electron probe microanalysis (EPMA), the phases in the alloys, such as Si-based solutions, Ti(Nb)Si, Ti(Nb)Si2, Nb(Ti)Si2, Ti(Nb)5Si4, Nb(Ti)5Si3, Ti(Nb)5Si3, Nb(Ti)3Si and Nb-based solutions are identified, and the phase evolution is analyzed. As a result, the microstructural and microchemical evidence provides a clear definition of the Nb-Si-Ti liquidus surface projection and indicates that the ternary phase diagram has seven transition reactions.