Repair of directionally solidified superalloy GTD-111 by laser-engineered net shaping

摘要

GTD-111 directionally solidified superalloy was repaired by the Nd:YAG laser based laser-engineered net shaping (LENS) process. Selection of process parameters are discussed against the formation of deposits and occurrence of defects. Formation of microfissures, porosity, lack of fusion, and stray crystals in the deposit zone was studied. It was identified that formation of stray crystals in the directionally solidified alloy could be due to two types of sources: the shape of the melt pool, and the existence of second-phase particles at the melt pool fusion boundary.