Inclusions　are　important　phases　affecting　material　properties　in　complicated　ways.　In　this　paper,　a　quantitative　study　of　the　addition　of　HfO2　inclusions　to　DZ125　nickel-based　superalloys　was　performed.　Experimental　results　showed　that　the　introduction　of　HfO2　inclusions　caused　a　loss　of　strength　and　ductility.　The　carbide　morphology　also　changed　significantly　from　skeletal-shaped　to　block-shaped,　resulting　in　a　remarkable　discrepancy　in　the　fracture　behavior　under　quasi-in-situ　tensile　testing.　The　SEM　dynamic　observations　showed　that　cracks　were　initiated　from　the　skeletal　carbides　and　almost　failed　to　propagate　into　the　matrix.　In　contrast,　the　damage　behavior　of　block-shaped　carbides　also　involved　internal　cracking　but　with　a　tendency　to　form　interconnected　microcracks　during　propagation.　A　crystal　plasticity　finite　element　model　(CPFEM)　method　was　further　developed　to　study　the　stress/strain　behavior　during　the　deformation　process,　considering　the　crystal　orientations　and　microstructure　morphologies　from　the　EBSD　data.　Those　elastoplastic　parameters　were　determined　through　nanoindentation　experiments.　Simulation　results　verified　that　blocky　carbides　produced　a　pronounced　strain　concentration　at　the　interface　of　the　carbides　and　matrix,　thereby　increasing　the　tendency　of　crack　formation.　This　paper　provides　a　fundamental　understanding　of　the　role　of　inclusions　in　material　recycling　applications.