Microstructure evolution and formation mechanism of laser-ignited SHS joining between Cf/Al composites and TiAl alloys with Ni–Al–Ti interlayer

In this study, Cf/Al composites and TiAl alloys were joined by a new method named laser-ignited self-propagating synthesis (SHS). Mixed powders of 63.0Ni–31.9Al–5.1Ti (wt%) were used as joining interlayer. Perfect joint was got. The microstructure evolution and formation mechanism of the SHS joint were investigated by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Results show that localized melting occurs on both sides. One γ-Ni0.35Al0.30Ti0.35 and two Ni–Al reaction layers form, respectively, in the TiAl/interlayer and Cf/Al/interlayer interfaces. The combustion of Ni–Al–Ti interlayer begins with the sharp reaction of Ni and Al. The interlayer product is a eutectic organization of NiAl and Al-rich γ.