Aging Thermal Treatment in the Inconel 725 Brazed Incorporating Tungsten Nanoparticles

Fractures in blade sections of Inconel 725 were impregnated with tungsten nanoparticles and jointed by the brazing process. In order to evaluate their effect over the microstructure, aging thermal treatments at 750 degrees C for 2, 6, 10, and 14 h were done. BNi-9 was selected as brazing filler metal and was characterized by scanning electron microscopy and X-ray fluorescence. Before brazing, the fractures were impregnated with a mixture of tungsten NPs in ethanol. Measurements of Vickers microhardness showed an increase in the melting zone of samples with aging thermal treatment for 14 h, which is attributed to the precipitation of the gamma' phase with a typical size of ca. 100 nm. Likewise, the tungsten NPs modified the size and morphology of Cr-Ni eutectics into finer and uniformly distributed microstructures.