激光区熔定向凝固Gd5Si2Ge2合金的显微组织特征

In this work, Gd5Si2Ge2 alloy was prepared the arc-melt method under the protection of argon atmosphere. Then the alloy was cut and directional solidified with the help of laser remelting rapid solidification technique. Microstructure of the as-cast and directional solidified Gd5Si2Ge2 were investigated in this work. It is found line features crossing or paralleling with each other are dominant in column cellular grains of the as-cast alloy. In the laser remelting directional solidified alloy, orientated lamellar structures are observed and the lamellar space increases slightly with the increase of the laser remelting velocity. Chemical analysis indicates the Ge is rich in lamellar and poor in lamellar space.