Abstract: The effect of solidification r ate on the microstructures of directionally solidified superalloyDZ22 is studied wit h the help of ZMLMC directional solidification equipment which has a super hightemperatur e gradient . The r esults show that the size and shapes of Cc , (C+ Cc) and MC change ser i2ously with the increase in cooling r ate. When t he cooling rate is equal to 54. 2K# s- 1, Cc particles dis2tribute evenly; bot h eutect ic (C+ Cc) in group block and MC in block distr ibute in interdentr itic zone.

Key words: cast ing, heat resistant alloys, cooling, rates, cr ystallization, structures, analyzing