反应堆压力容器钢A508-3辐照硬化的剂量率效应研究

针对不同剂量率对国产反应堆压力容器钢(Reactor Pressure Vessel, RPV)A508-3辐照硬化的影响，利用3.5 MeV的Fe离子在3种不同剂量率(0.1, 0.5和 1.0 dpa/h)下将样品辐照至4个不同剂量点(0.1, 0.3, 1.0和3.0 dpa)，采用纳米压痕技术表征样品在不同辐照条件下的硬化效应。结果表明，在高剂量率(1.0 dpa/h)下，材料的硬度随剂量的增大快速增加，在0.3 dpa以后逐渐达到饱和；中剂量率(0.5 dpa/h)和低剂量率(0.1 dpa/h)下，样品硬度随剂量的变化趋势与高剂量率相似，但在0.3 dpa以后材料的硬度随剂量仍在缓慢增加。在辐照剂量低于0.3 dpa时，不同剂量率引起的辐照硬化差异较小，但在辐照剂量大于0.3 dpa时，不同剂量率辐照下的硬化效应差异显著。数据拟合结果表明，在实验剂量范围内辐照硬化的饱和值随剂量率的增加呈减函数关系。

Effect of the Dose Rate on Irradiation Hardening of Reactor Pressure Vessel Steel A508-3

To study the effect of dose rate on irradiation hardening of the reactor pressure vessel steel (A508-3), the specimens of RPV steel were irradiated by 3.5 MeV Fe ions to four doses (0.1, 0.3, 1, 3 dpa) at three different dose rates (0.1, 0.5 and 1 dpa/h), respectively. Nano-indentation technique was used to characterize the change in hardness after irradiation. At high dose rate(1.0 dpa/h), the results indicated that irradiation hardening increases rapidly with dose and tends to saturation at the dose higher than 0.3 dpa. Compared to that with high dose rate, the hardness increment showed similar behavior at low dose rate(0.1 dpa/h) and medium dose rate(0.5 dpa/h), but it still increased gradually at dose higher than 0.3 dpa. When dose is lower than 0.3 dpa, a small difference showed in irradiation hardening under different dose rates irradiation, but the difference became significant when the dose was higher than 0.3 dpa. At present dose regime, the irradiation hardening was found to be inversely proportional to the dose rate.