Thermodynamic theory was used to calculate the formation temperature and site fraction of MC carbides in Fe–C–Ni–V–Ti system. The calculation results showed the theoretical formation conditions of core–shell MC carbides. One-step and two-step heat treatment processes were used in Fe–C–Ni–V–Ti alloy to, respectively, obtain homogeneous and core–shell MC carbides, which was consistent with the thermodynamic calculation results. The transmission electron microscopy observations showed that the core–shell MC carbide obtained by the two-step heat treatment process contained homogeneous (Ti, V)C as the core and basically VC as the shell. The mechanical test results proved that compared with homogeneous MC carbides, core–shell MC carbides could improve the basic mechanical properties of the alloy because VC shell greatly increased the bonding strength and separation work of Fe/MC interface. Thus, the core–shell MC carbide with a VC shell structure can be a better grain refiner and can be used in steels with a high standard of fracture toughness.

热力学理论用于计算Fe–C–Ni–V–Ti系统中MC碳化物的形成温度和部位分数。计算结果表明了核壳MC碳化物的理论形成条件。Fe–C–Ni–V–Ti合金分别采用一步和两步热处理工艺，以获得均质和核-壳MC碳化物，这与热力学计算结果是一致的。透射电子显微镜观察表明，通过两步热处理工艺获得的核-壳MC碳化物包含均匀的（Ti，V）C作为核，基本上是VC作为壳。力学测试结果证明，与均质MC碳化物相比，核壳型MC碳化物可以改善合金的基本力学性能，因为VC壳大大提高了Fe / MC界面的结合强度和分离功。因此，具有VC壳结构的核-壳MC碳化物可以成为更好的晶粒细化剂，并且可以用于断裂韧性较高的钢中。