Nickel aluminum bronze（NAB）is one of the main materials used for making ship propellers. Large ship propellers are generally castings. The coarse and inhomogeneous microstructure of the cast NAB will reduce the lifetime of the ship propellers. In present study

laser surface melting（LSM）is applied to modify the cast microstructure. The results show that the LSM significantly refines the cast microstructure. The melting zone contains fine columnar grains

and the major axis of the columnar grains is perpendicular to the interface of the molten pool. The heat affected zone（HAZ）consists of coarse isometric and columnar grains. The hardness of the LSM NAB can reach 285

3

25 HV

which is increased by 50%

7

0% comparing with the hardness of the cast one. The electrochemical measurement results show that the LSM NAB and cast NAB experience similar electrode reaction processes in 3.5% Na Cl solution. However

comparing with the cast NAB

the cathode process of the LSM NAB is slower and therefore the corrosion rate is slower. The ultrasonic vibration cavitation erosion test results show that the erosion rate of the LSM NAB is only 60% of that of the cast one because of the increased hardness and refined microstructure. For LSM NAB

the damaged surface is much evener

and no large cavitation erosion pit is found. And the effect of LSM parameters on the microstructure

corrosion and cavitation erosion behavior is also discussed.