The investigation of bondability of Ni-Ti alloys by powder metallurgy method with the diffusion bonding

In this study, the by cold pressing manufactured Ni-Ti composites were joined withdiffusion bonding techniques. Metal tatrix composite (MMC) material has been produced asmixture with a average dimension of 45µm and with a chemical composition of 51 % Ni-49 %Ti in weight percent. In this study two parts with same chemical composition MMC were joinedby use diffusion welding technique. The bonding of MMC parts were relaized under the samepressure, at different temperatures and durations. Particularly, the Ni-Ti rate in the weldingregion was examined.The manifactured samples were cut in a suitable dimensions and they have been joinedin a diffusion furnace with diffusion welding method. Diffusion welding process were madeunder argon inert gas atmosphere, with a constant load of 500 N, under the temperature of 850,875, 900 and 925ºC and, in 20, 40 and 60 minutes experiment time. After the weldingprocesses, samples were cut perpendicular to the welded surface, the microstructure wereexamined by SEM and EDS analysis on the near of bonded surface layer, and also matrix.the optical microscopy photos have been shown that the bonded composite materials hadahomogen structure and a minimumhole level. It was also observed that the Ni-Ti rates hadapproximately, the same values in different point of the test materials.Keywords: Cold pressing, Ni-Ti, MMC, diffusion bonding, powder metallurgy,