摘要
研究了含Nb低合金高强钢在不同时效工艺下的力学性能和显微组织,并采用扫描电镜(SEM)和透射电镜(TEM)及原位分析方法研究了时效过程中试验钢的位错组态和含Nb碳化物的析出规律。结果表明,与原始态相比,随着时效温度的增加,试验钢的强度增加,塑性和韧性降低。显微组织TEM观察和原位分析结果表明,在200~300℃时效温度范围内,随着时效温度的增加,试验钢中的位错密度大幅降低,时效诱发了含Nb碳化物的大量析出,时效后试验钢的强度增加是NbC析出强化的结果。
Mechanical properties and microstructure of low alloy high strength steel containing Nb with different aging processes were studied. The dislocation configuration and the precipitation of Nb-containing carbides in the tested steel during aging were studied by means of scanning electron microscopy(SEM), transmission electron microscopy(TEM) and in-situ analysis. The results show that compared with the original state, the strength of the tested steel increases and the ductility and toughness decrease with the increase of aging temperature. The results of TEM observation and in situ analysis of microstructure show that the dislocation density in the tested steel decreases significantly with the increase of aging temperature in the range of 200-300 ℃, and the aging induces a large amount of precipitation of NbC carbides. The strength of the tested steel increase after aging is due to the NbC precipitation strengthening.
引文
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