利用透射电镜观察、能谱分析以及三维原子探针分析微观原子分布等方法,结合热稳定性实验数据,对含铌热作模具钢SDH8Nb中碳化物的形态、大小及其变化情况和对材料热稳定性能的影响进行了研究。结果表明:SDH8Nb钢的热稳定性明显优于传统的H13钢。淬回火后,在SDH8Nb钢中,主要碳化物为垂直态的长棒状Mo2C型碳化物,以及少量的Cr和V的碳化物,而Nb元素在淬回火后固溶到基体中,经过长时间保温后,以NbC的形式析出,提高了材料的抗回火软化能力。 The morphology, size and variation of carbides in niobium-containing hot work die steel SDH8Nb were investigated by transmission electron microscopy, energy dispersive spectroscopy and three-dimensional atomic probe microanalysis, combined with the experimental data of thermal stability. The effect of stability is studied. The results show that the thermal stability of SDH8Nb steel is obviously better than the traditional H13 steel. After quenching and tempering, in SDH8Nb steel, the main carbides are the long rod-shaped Mo2C carbides in the vertical state and a small amount of carbides of Cr and V, while the Nb elements are solid-solved into the matrix after quenching and tempering, Time insulation, the precipitation in the form of NbC, improve the material anti-temper softening ability.