Abstract: The solidified microstructure of Ni-5wt% Cu alloy is researched at the cooling velocity range of 13～130K/s with zone melting unidirectional solidification apparatus. It indicates that the crystals with different crystal growth orientations have different solidified microstructures in the condition of G L=1 300K/cm,υ=500μm/s: the crystal with solidified orientation <100>is dendrite; the crystal with solidified orientation <120> is superfine cell. The crystals have different superfine cellular spacing due to the crystal growth orientation with G L=1 300K/cm, υ=800μm/s: superfine cellular spacing of the crystal with solidfied oriention <100> is 28μm, and that of the crystal with solidified oriention <21 1 > is 16. 5μm. In a grain, two parts have different microstructures due to the different orientations under the same solidification parameters. In hyporapid solidification, dendritic solidified orientation isn′t the preferential direction <100>; the preferential orientation is disposed in the superfine cellular growth process.

Key words: crystal growth, bearing, cooling, velocity, crystallites, crystallization, shapes