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建立规则溶液亚点阵模型计算了不同温度(1073～1523 K)下低碳Nb--Ti二元微合金钢(Nb质量分数为0.023%,Ti质量分数为0.012%)中碳氮化物析出相的平衡摩尔分数、化学驱动力和各组元摩尔分数,对微合金钢中析出粒子演变规律进行研究,并利用透射电镜观察及能谱分析验证这种析出模式.计算结果表明,1523 K下析出粒子化学式组成为(Nb0.15Ti0.85)(C0.16N0.84),由富Ti的析出物逐渐过渡至Nb--Ti均匀析出,析出粒子演变顺序为(Nb0.15Ti0.85)(C0.16N0.84)、(NbxTi1-x)(CyN1-y)和(Nb0.5Ti0.5)(C0.56N0.44),与实验结果符合较好.随着温度降低,Ti/Nb质量比逐渐减小,得到的TiC比NbC更难溶.对均匀形核及位错处形核的临界核心尺寸和相对形核速率进行计算,得到最大形核率即可获得最细小第二相尺寸的温度.
The sub - lattice model of regular solution was established to calculate the precipitation phase of carbonitride in low carbon Nb - Ti binary microalloyed steel (0.023% of Nb and 0.012% of Ti) at different temperatures (1073 ~ 1523 K) The equilibrium molar fraction, the chemical driving force and the molar fraction of each component, the evolution law of precipitated particles in microalloyed steel was studied, and the precipitation pattern was verified by transmission electron microscopy and energy spectrum analysis. The calculated results show that the precipitation at 1523 K The chemical composition of the particles is (Nb0.15Ti0.85) (C0.16N0.84). The transition from Ti - rich precipitates to Nb - Ti is uniform and the order of evolution is (Nb0.15Ti0.85) (C0. 16N0.84), (NbxTi1-x) (CyN1-y) and (Nb0.5Ti0.5) (C0.56N0.44), which are in good agreement with the experimental results.As the temperature decreases, the mass ratio of Ti / Nb decreases The obtained TiC is more insoluble than NbC.The critical core size and relative nucleation rate of uniform nucleation and dislocation nuclei are calculated, and the maximum nucleation rate can be obtained to obtain the temperature of the smallest second phase size.