Superplastic behaviour and concurrent microstructural evolution in microduplex alloys are reviewed to bring out the following less common trends reported in the literature. An anomaly exists about the shape of the log (stress)-log (strain rate) curves and the parameters of the constitutive relationship. Also, some microduplex alloys exhibit two values of activation energy for superplastic deformation with a lower value at T ≲ 0.8Tm. The ratio of the two activation energies is approximately equal to 0.55. The co-existing two phases and the α/α, α/β and β/β boundaries contribute differently to deformation and cavitation, but grain coarsening occurs in a concerted manner.