Yang Wanhuan, Qian Jin, Zhong Weihua, Ning Guangsheng, Peng Shunmi, Yang Wen
Reactor Engineering Technology Research Institute, China Institute of Atomic Energy, Beijing 102413, China.
Materials (Basel). 2023 Jan 5;16(2):544. doi: 10.3390/ma16020544.
LT21 a type of aluminum alloy used for the irradiation channel of the first heavy water research reactor (HWRR) in China. Studying the mechanical property of irradiated LT21 aluminum under actual service conditions is essential for evaluating its application property. In this paper, tensile specimens of irradiated LT21 were manufactured from the decommissioned irradiation channel of an HWRR; then, tensile tests were carried out, and then the fracture surfaces were observed. The effect of neutron irradiation on tensile behavior and the failure mechanism was analyzed by comparing the result of irradiated and unirradiated LT21 specimens. The results show that, with the thermal neutron flux increasing to 2.38 × 10 n/cm, the YS gradually increased from the initial 158 MPa to 251 MPa, the UTS increased from 262 MPa to 321 MPa, and the elongation decreased from 28.8% to about 14.3%; the brittle fracture of the LT21 specimen appeared after irradiation, and the proportion of brittle fracture increased as the neutron fluence increased; the nanophase structures, with a size of less than 50 nm, were precipitated in the LT21 aluminum alloy after neutron irradiation. Transmutation Si is presumed to be the main cause of the radiation effect mechanism of LT21.
LT21是一种用于中国第一座重水研究堆（HWRR）辐照通道的铝合金。研究辐照后的LT21铝合金在实际服役条件下的力学性能对于评估其应用性能至关重要。本文从一座已退役的重水研究堆的辐照通道中获取了辐照后的LT21拉伸试样，然后进行了拉伸试验，并观察了断口表面。通过对比辐照和未辐照的LT21试样的结果，分析了中子辐照对拉伸行为和失效机制的影响。结果表明，随着热中子通量增加到2.38×10 n/cm，屈服强度从初始的158 MPa逐渐增加到251 MPa，抗拉强度从262 MPa增加到321 MPa，伸长率从28.8%降至约14.3%；辐照后LT21试样出现脆性断裂，且脆性断裂比例随中子注量增加而增大；中子辐照后，LT21铝合金中析出了尺寸小于50 nm的纳米相结构。嬗变硅被认为是LT21辐射效应机制的主要原因。
