The microstructure of W-8 pct Mo-7 pct Ni-3 pct Fe alloy has been found to evolve in concomitance with the reprecipitation of tungsten atoms from the matrix phase onto the grains. With increase in isothermal holding time at 1480 degrees C, the concentration of tungsten in the matrix phase reduces from 53.7 wt pct for an isothermal holding time of 5 minutes, and gradually approaches an equilibrium value of about 18 wt pct. The continuous solid-liquid reactions result in gradual penetration of the liquid phase into the boundaries of the skeletal solid grains. Consequently, contiguity of the tungsten based grains drops sharply during the initial stage of isothermal holding, and reaches minimum after an isothermal holding time of 120 minutes. The contiguity subsequently increases again as the coalescence of grains commences. Simultaneous diminishing of the concentration of tungsten in the matrix phase along with decrease in contiguity of the grains result in an optimal combination of mechanical properties after an isothermal holding time of 120 minutes. Molybdenum has been found to bring about a substantial microstructural refinement, whereby a mean grain size of only 22 mu m is attained from an isothermal holding time of as long as 240 minutes.