Rapid Solidification and Phase Composition of Gd-16wt%Co Alloy in Laser Melting Conditions

Abstract

Solidification microstructure of Gd-16wt%Co master alloy is characterized by the primary (Gd), CoGd3, and Co7Gd12 dendrites plus (Co3Gd4+Co7Gd12) eutectic. In the laser melting conditions, the rapid solidification of melting pool shows three layers along the radial direction. The size of melting pool decreases with the increase of scanning speed. The dendrites are refined and the eutectic disappears in the pool. Near the top of the pool, the metastable phases and the peritectic reaction are restrained in the rapid solidification conditions.