Neutron-flux effects on irradiation-induced hardening and microstructures in a reactor pressure vessel steel were studied. An A533B-type steel containing no Cu was neutron-irradiated with fluxes of 1 × 10¹⁴ n/cm²/s (high-flux) or 1 × 10¹² n/cm²/s (low-flux) to the same fluence of approximately 3 × 10¹⁹ n/cm², and the same temperature of approximately 290 °C. The recovery behavior of irradiation-induced defects and irradiation-hardening, ΔHv, was investigated by post-irradiation isochronal annealing from 275 to 450 °C. In both the high- and low-flux cases, the recovery behavior of ΔHv and the average positron lifetime, τ_ave, corresponded well to the annealing, suggesting that defects in which positrons are trapped are the origin of irradiation-hardening. The values of ΔHv and τ_ave in the high-flux sample started to recover at around 350 °C, while those in the low-flux sample started to recover at around 400 °C. Thus, in the high-flux sample, unstable defects transiently existing at low temperature but annealed out at around 350 °C, are indicated. Such defects are suggested to be defect-(Mn, Ni, Si) complexes, where the nature of the defect is that of a mono-vacancy and/or dislocation loops.

研究了中子通量对反应堆压力容器钢中辐射诱发的硬化和组织的影响。用1×10 ¹⁴ n / cm ² / s（高通量）或1×10 ¹² n / cm ² / s（低通量）的通量对无Cu的A533B型钢进行中子辐照。大约3×10 ¹⁹ n / cm ²，相同的温度大约290°C。通过在275至450°C下进行辐照后等时退火，研究了辐照引起的缺陷和辐照硬化ΔHv的恢复行为。在高通量和低通量情况下，ΔHv的恢复行为和平均正电子寿命，τ _AVE，以及对应于退火，这表明在该正电子被捕获该缺陷被照射硬化的原点。的值ΔHV和τ _AVE高通量样品中开始在约350℃以回收，而低通量样品中开始，在400℃左右进行恢复。因此，在高通量样品中，表明了在低温下短暂存在但在350℃左右退火的不稳定缺陷。这些缺陷被认为是缺陷-（Mn，Ni，Si）络合物，其中缺陷的性质是单空位和/或位错环的性质。