Abstract:A high Al+Ti containing Ni-based wrought superalloy ingot was prepared by a vacuum induction furnace. Then the ingot was remelted into three with different Zr contents in the same furnace. After as-cast microstructures observation, these ingots were homogenized. The effect of Zr on microstructures evolution during the homogenization process was emphatically studied. The results show that the Zr addition has no obvious influence on the initial grain size of the ingots, but significantly promotes the non-equilibrium solidification eutectic (γ + γ′) and Zr rich phase precipitation, especially at the grain boundary. Besides, Zr significantly promotes the formation of micropores in the interdendritic region. After homogenization, the non-equilibrium phases have been completely dissolved, the dendrite segregation has been obviously reduced and the original grains have grown obviously. Interestingly, the higher the Zr content is, the more obvious the grain growth is. Besides, the size and area fraction of micropores have increased markedly compared with those in the as-cast microstructure, and the micropores formation in the as-homogenized microstructure also increases significantly with the increase of Zr content. Zr increases the micropores formation in the as-cast alloy is mainly related to the enrichment of Zr in residual liquids which retarding the alloy solidification. The principal reason why Zr promotes the grain growth and micropores formation during homogenization is that the more eutectic (γ + γ′) and Zr-rich phase formation aggravates the interdiffusion between solute elements.