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T he eVect of solidification rate on the formation of g phase in a directionally solidified IN792+Hf superalloy was studied. A Cr rich 'precipitate free zone' adjacent to the eutectic (c+c∞) was noticed in the quenched directionally solidified microstructure of the alloy. T he formation of the precipitate f ree zone was due to the solidification of eutectic (c+c∞) which consumed a large amount of the c∞ forming elements and increased the ratio of (T i+Hf +T a+W)/Al in the residual liquid. T he high ratio of (T i+Hf +T a+W)/Al in the final residual liquid induced the formation of g phase and hence g phase always appeared at the boundary between the eutectic regions and the dendrite core regions. T he ratio of (T i+Hf +T a+W)/Al was decreased by the diVusion of elements between the residual liquid and the surrounding area. A lower solidification rate favoured the back diVusion and decreased the ratio of (T i+Hf +T a+W)/Al in the residual liquid, and hence reduced the formation of g phase.MST /4279