In order to reduce the"stray grain"presented in laser restoration layer on single crystal superalloy

an energy-retrained laser epitaxial restoration（ERLER）process was put forward.The effects of laser power and the width of single crystal superalloy base metal on the morphology and microstructure of restoration layer were investigated.The results reveal that

the restoration layer produced by ERLER process possesses directionally epitaxial grains in almost entire layer

and the formation probability of"stray grains"is decreased greatly.Under the optimized parameters

continuous epitaxial grains can be obtained in restoration layer with a thickness of 1 220μm.With the increase of laser power

the layer thickness is increased to some extent.At the same laser power and laser spot diameter

the layer thickness is increased and then decreased with flattening morphology when the base metal width is increased.For the case of 3 mm width

obvious flow paths are presented in the restoration layer.Combined with the photos taken by high-speed camera

the flow behavior in the laser molten pool can be revealed as follows:the metal firstly rised up from bottom of molten pool center to surface and spreaded to around

then flowed back to the center bottom along with the molten pool bottom.