The　diverse　shapes　and　multi-component　characteristics　of　complex　carbides　in　nickel-based　superalloys　play　a　crucial　role　in　determining　their　mechanical　properties.　However,　relying　solely　on　experimental　evaluations　poses　challenges,　making　analog　simulations　essential.　This　study　investigates　the　structural,　mechanical,　and　electronic　properties　of　skeletal　and　blocky　carbides　in　the　DZ125　superalloy　using　first-principles　calculation　and　experimental　methods.　The　carbides　analyzed　include　Ti0.125Ta0.625Hf0.25C　and　Ti0.125Ta0.25Hf0.625C,　which　differ　in　their　Ta　and　Hf　ratios.　The　results　indicate　that　Ti0.125Ta0.625Hf0.25C　exhibits　superior　mechanical　properties　compared　to　Ti0.125Ta0.25Hf0.625C,　along　with　enhanced　fracture　toughness　and　higher　energy　requirements　for　crack　propagation.　Electronic　characteristic　analysis　reveals　that　Ti0.125Ta0.625Hf0.25C　possesses　greater　thermodynamic　stability　due　to　the　presence　of　more　valence　electrons　in　Ta　atoms,　which　form　stronger　covalent　and　metallic　bonds.　Additionally,　quasi-in-situ　tensile　testing　confirms　that　skeletal　carbides　exhibit　higher　cracking　resistance　compared　to　blocky　carbides.　This　study　enhances　our　understanding　of　the　stability　of　these　carbides　and　provides　valuable　insights　for　the　design　and　optimization　of　DZ125　superalloys.　©　2024　Elsevier　Ltd