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研究了00Cr25Ni7Mo4N超级双相不锈钢在600～1 000℃不同温度时效以及920℃和830℃等温时效过程中的χ相析出规律,利用扫描电镜的背散射电子探测器观察了χ相的析出数量和分布,采用透射电镜和X射线能谱仪分析了χ相的结构和成分。结果表明,χ相的析出温度范围在750～920℃之间,其峰值温度约为830℃。相比σ相,χ相析出数量较少,主要分布在α/γ相界和α/α晶界。从等温时效过程看,00Cr25Ni7Mo4N钢中χ相的析出经历了孕育、快速析出、达到饱和以及逐渐转变为σ相的系列过程,表明χ相是一种亚稳相,随着时效时间的延长,χ相会转变为σ相。
The χ-phase precipitation regularity of 00Cr25Ni7Mo4N super duplex stainless steel at 600 ~ 1 000 ℃ and the isothermal aging at 920 ℃ and 830 ℃ were investigated. The number and distribution of χ-phase precipitates were observed by backscattering electron detector (SEM) , The structure and composition of χ phase were analyzed by transmission electron microscopy and X-ray energy dispersive spectroscopy. The results show that the precipitation temperature range of χ-phase is between 750 and 920 ℃, and the peak temperature is about 830 ℃. Compared with the σ phase, χ phase precipitates less, mainly in the α / γ phase boundary and α / α grain boundary. From the isothermal aging process, the precipitation of χ phase in 00Cr25Ni7Mo4N steel has undergone a series of processes of inoculation, rapid precipitation, reaching saturation and gradually changing to σ phase, indicating that χ phase is a metastable phase. With the extension of aging time, χ Phase change into σ phase.