Microstructural development in the dual phase intermetallic alloy Ni50Al25Be25

Recent experimental results on the liquidus surface in the Ni–Al–Be ternary system suggests a eutectic reaction within a pseudo-binary NiAl–NiBe isopleth at 1660 K and at a composition of approximately 30 a/o Be, 20 a/o Al. The intent of this study is to investigate the NiAl–NiBe isopleth, beginning with the microstructural development of an alloy (Ni50Al25Be25) near the reported eutectic reaction. Extraordinarily fine microstructures are observed in the alloy Ni50Al25Be25, both in the as-cast condition and after heat treatment. These structures consist of B2 NiAl and NiBe, in both single phase and two phase morphologies. These microstructures are discussed in terms of the previously proposed ternary phase diagram for this system.