双相不锈钢热老化的三维原子探针研究

发布时间：2018-07-04 07:31

本文选题：双相不锈钢 + 热老化　；参考：《南京理工大学》2017年硕士论文

【摘要】：核电站的安全营运是核电发展过程的基础,研究核电站一回路主管道用双相不锈钢的热老化过程对核电站建设具有重要指导意义。本文研究了来自法国、国内Y厂商和国内G厂商生产的三种不同双相不锈钢材料,结合扫描电子显微镜(SEM)、纳米硬度仪、冲击试验机和三维原子探针(APT)技术,系统的分析双相不锈刚长时间热老化过程中,宏观机械性能、微观组织以及原子空间分布的演变规律;分析不同厂商生产的双相不锈钢的宏观和微观差异。对同一温度不同热老化时间的研究表明,随着热老化的时间延长,铁素体相的硬度显著增加,断裂冲击功急剧下降,材料由韧性断裂转变为脆性断裂。铁素体中发生了相分解,形成了 α'相和α相,并且有等轴的G相形核长大。α/γ相界面上有明显的元素偏析,还析出了 G相。在相界面附近出现了无G相析出区域,这个区域的特征与铁素体其他位置的特征不相同。对不同厂商生产的双相不锈钢进行相同的热老化研究表明,国内目前已经能够独立生产符合国际标准的一回路主管道双相不锈钢。Y厂商生产的钢种性能甚至比法国产的更好。不同厂商生产的钢种微观组织有非常大的区别,这一研究对于厂商改进生产技术有积极作用。
[Abstract]:The safe operation of the nuclear power plant is the foundation of the nuclear power development process. The research on the thermal aging process of the dual phase stainless steel in the primary pipeline of the nuclear power plant is of great significance to the construction of the nuclear power plant. This paper studies three different duplex stainless steel materials produced from the French, domestic Y manufacturers and domestic G manufacturers, combined with the scanning electron microscope (SEM). The microhardness tester, impact tester and three dimensional atomic probe (APT) technology are used to systematically analyze the macroscopic mechanical properties, microstructures and the evolution of the atomic spatial distribution during the long time thermal aging process of the dual phase stainless steel, and analyze the macroscopic and microscopic differences between the two phase stainless steel produced by different manufacturers. The study shows that the hardness of the ferrite phase increases significantly with the time of thermal aging, the impact work of the fracture is sharply decreased and the material is transformed from ductile fracture to brittle fracture. The phase decomposition of the ferrite has occurred, the phase of alpha and alpha is formed, and the G phase nucleus of the equal axis grows. There are obvious elements segregation on the interface of the alpha / gamma phase and the precipitation of G. Phase. There is no G phase precipitation area near the phase interface. The characteristics of this region are different from the other positions of the ferrite. The same thermal aging study on the duplex stainless steel produced by different manufacturers shows that the domestic production of double phase stainless steel.Y manufacturer in charge of the first circuit in line with the international standard has been produced at present. Steel properties are even better than those made in France. The microstructure of steel produced by different manufacturers is very different. This study has a positive effect on the improvement of production technology by manufacturers.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG142.71

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