质子辐照对RPV材料组织和性能的影响

论文总字数：22888字

摘 要

反应堆压力容器（RPV）是反应堆最大的不可更换的核心部件，其使用寿命直接决定了整个核电站的服役寿命。辐照脆化是RPV材料的主要失效方式，然而，关于RPV材料在高注量辐照条件下的试验数据还较少，有必要对国产RPV材料在高注量辐照条件下的组织和性能变化规律进行系统的研究。本文采用质子辐照模拟中子辐照，探索国产A508-3钢在不同注量辐照条件下微观组织和力学性能的变化。

在室温下，进行190keV的电子辐照，辐照注量分别为0.053、0.108、0.162、0.216、0.271dpa,等效于RPV 服役20 、40 、60、80 和100 年的质子辐照注量。利用金相显微镜和透射电子显微镜观察了辐照前后样品的显微组织，结果表明，国产A508-3钢的显微组织为粒状贝氏体，粒状贝氏体由板条状贝氏体铁素体基体和马氏体/奥氏体岛状组织组成。质子辐照对板条数量密度及分布、碳化物尺寸均没有明显影响。质子辐照后A508-3 钢内部产生了高数量密度的位错环，位错环直径范围约为1.0nm-20.0nm，绝大多数位错环尺寸在2.0nm-5.0nm 。大部分的位错环柏氏矢量为b=lt;0 0 1 gt; ，且大都为间隙原子型位错环。随着辐照注量增加，位错环的尺寸及数量密度均增加。利用纳米压痕实验测试辐照前后A508-3钢的力学性能，结果表明，A508-3 钢辐照之后弹性模量没有发生显著改变，但纳米硬度值随辐照注量增加而增加，增速变缓，直到本次实验最高的辐照注量，仍然呈现为增加趋势，没有出现饱和现象.本文用幂函数拟合了位错环引起的强化和脆化关系式，也表征了屈服强度增量和转变温度增量随辐照注量变化的关系式。

关键词：反应堆压力容器钢；质子辐照；微结构损伤；位错环；辐照硬化和脆化

Abstract

The reactor pressure vessel (RPV) is the core component of the largest nuclear reactor, and its service life directly determines the service life of the nuclear power station. Irradiation embrittlement is the main failure mode of RPV materials, however, the experimental data of RPV material in high irradiation is less. It is necessary to study the structure and properties of the domestic RPV material under high irradiation. In this paper, proton irradiation is used to simulate neutron irradiation to explore the microstructure and mechanical properties of A508-3 steel under different irradiation..

In the present work, 190 keV proton are conducted on a A508-3 steel to 0.053,0.108,0.162,0.21,0.271 dpa at room temperature, which equal to the 20,40,60,80,100 years.

The microstructure of the samples before and after irradiation was observed by optical microscope. The result indicate that the microstructure of the domestic A508-3 steel is granular bainite, and granular bainite is composed of the ferrite matrix and martensite / austenite island structure. The obtained results show that irradiation-induced defects are mainly dislocation loops，majority of which are both of lt;0 0 1gt;type and of interstitial type,without the observation of the micro-voids. In this paper, the relationship between the reinforcement and embrittlement caused by dislocation ring is fitted by power function, and the relationship between yield strength increment and temperature increment of the increment of the change of the irradiation dose is also characterized.At last, nano indentation experiment was conducted to express the mechanic properties. The modulus of elasticity was not changed obviously and The hardness value increased with the increase of the irradiation dose whose growth rate tends to ease. In this paper, the relationship between the reinforcement and embrittlement caused by dislocation ring is fitted by power function, and the relationship between yield strength increment and temperature increment of the increment of the change of the irradiation dose is also characterized.

目录

摘要...............................................................I

Abstract..........................................................II

1. 绪论........................................................1

1.1 核能概况.....................................................1

1.2 核反应堆材料的性能要求......................................2

1.3 反应堆压力容器及材料要求.....................................3

1.4 质子辐照对材料的损伤机理.....................................3

1.5 课题意义和内容...............................................4

1. 试验过程及方法..............................................5

2.1 试验材料.....................................................5

2.2 质子辐照....................................................5

2.3 金相试样制备及组织观察.......................................6

2.4 透射电镜试样制备及TEM实验...................................6

2.5 纳米压痕实验的原理和方法.....................................7

1. 质子辐照后RPV组织与性能变化规律..........................10

3.1 显微组织....................................................10

3.2 辐照产生的位错环的形态......................................11

3.3 位错环的尺寸分布和数量密度的测量结果........................12

3.4 纳米压痕仪实验结果.........................................13

第四章 对微结构演变及力学性能变化的分析与讨论....................15

4.1 质子辐照引起的微观变化分析与讨论...........................15

4.2 对显微组织形貌和成分的分析..................................15

4.3 位错环引起的硬化和脆化的理论计算及分析.....................16

4.4 对辐照后力学性能变化的分析与讨论...........................16

第五章 结论......................................................17

致谢..............................................................18

参考文献..........................................................19

第一章 绪论

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