Abstract:The brazing microstructures varied from gap size, brazing time and filler metal flow path. There are four types of microstructure found in using the powder form Ti15Cu15Ni filler metal. The microstructure was examined by optical metallography, SEM, X-ray and EPMA. Ti-Cu-Ni phase diagram was assessed and two isopleths were estimated to interpret the microstructure morphology and phases formed. The formation of brazing microstructure can be well described from the principles of phase diagram, solidification path and phase transformation.