Transmission electron microscopy study of brazed joint microstructure in a Ni3Al-based intermetallic alloy IC 6 was performed. A continuously distributed microconstituents consisting of c solid-solution, M3B2-type and M23B6-type borides, which were likely formed by eutectic-type reaction(s) from residual liquated insert during cooling from brazing temperature, were observed along the joint centreline. Consideration of possible incipient melting due to eutectic-type transformation reaction of these phases is pertinent to development of post braze heat treatment for modifying the brazement microstructure.