高能重离子辐照下国产RPV钢A508-3的硬化行为

Hardening Behavior of China RPV Steel A508-3 Under Irradiation with High Energy Heavy Ions

目的研究在563 K的温度条件下,高能重离子辐照导致国产RPV钢A508-3的硬化行为。方法使用回旋加速器提供的352.8 MeV Fe^(21+)对A508-3钢试样进行辐照,使其依次达到0.15、0.30、1.50 dpa的损伤水平。借助辐照终端的梯度减能装置,在样品表面至25μm的深度范围内产生一个准均匀分布的原子离位损伤坪区,并使用纳米压痕仪和维氏显微硬度计测量了试样的硬度。结果考虑到压痕尺寸效应的影响,采用Nix-Gao模型对硬度数据进行拟合,由于高能Fe离子产生了较厚的损伤区,辐照试样中的软基效应明显减弱。辐照后的试样出现明显的硬化现象,且随着辐照剂量的增大,硬化增量有饱和趋势。通过辐照前和辐照至0.15 dpa试样的微硬度数据,得出其与纳米硬度之间的线性关系(Hv_(0)=0.85H_(0))。结论借助A508-3辐照前后的硬度数据,计算发现试样的屈服强度增量与辐照剂量之间存在一种幂函数关系,这为A508-3钢中子-离子辐照硬化的映射关系研究提供了基础数据。

The paper aims to study hardening behavior of Chinese domestic RPV steel A508-3 irradiated with high energy heavy ion at 563 K.Specimens of the A508-3 steels were irradiated with 352.8 MeV Fe^(21+) ions provided by a terminal of cyclotron to three successively increasing damage levels of 0.15,0.30 and 1.50 displacements per atom(dpa).A quasi-uniform atomic displacement plateau was produced in the specimens from the near surface to a depth of 25μm by using an energy degrader.A nanoindentor and a Vickers micro-hardness tester were used to measure the hardness of the specimens.Considering the influence of indentation size effect,the Nix Gao model is used to fit the hardness data.It is observed that the soft substrate effect can be diminished substantially in the irradiated specimens due to the thick damaged regions produced by the Fe ions.The results show that the hardening phenomenon is observable after irradiation,and the hardening increment tends to be saturated with the increase of irradiation dose.The linear relationship between microhardness and nanohardness(Hv_(0)=0.85 H_(0))was obtained by the microhardness data of 0.15 dpa sample before and after irradiation.A power law relationship between the yield strength increment and the irradiation damage dose is proposed based on the hardness data of A508-3 before and after irradiation,which provides basic data for the study of neutron-ion irradiation hardening mapping relationship of A508-3 steel.