Effect of silicon on ductility of T91 steel in liquid lead–bismuth eutectic environment
Ji Li1, Xi-kou He1, Gang Yang1, Bin Xu2, Zheng-xin Tang1
1 Research Institute of Special Steel, Central Iron and Steel Research Institute Co., Ltd., Beijing 100081, China 2 Design Institute, Nuclear Power Institute of China, Chengdu 610014, Sichuan, China
Effect of silicon on ductility of T91 steel in liquid lead–bismuth eutectic environment
Ji Li1, Xi-kou He1, Gang Yang1, Bin Xu2, Zheng-xin Tang1
1 Research Institute of Special Steel, Central Iron and Steel Research Institute Co., Ltd., Beijing 100081, China 2 Design Institute, Nuclear Power Institute of China, Chengdu 610014, Sichuan, China
摘要 The tensile tests of T91 and T91Si steels at 200–450 ºC in air and at 350 ºC in oxygen-depleted liquid lead–bismuth eutectic (LBE) environment with strain rate of 1 9 10–5–5 9 10–3 were performed. Results show that the activation energy of T91 steel is 103.45–246.76 kJ/mol and that of T91Si steel is 146.98–172.11 kJ/mol when Portevin–Le Chatelie (PLC) phenomenon occurs. The elongation reduction of T91 steel at 350 ºC is not specific to LBE environment, whereas the presence of LBE promotes crack initiation and propagation and affects the elongation of the material in the necking stage. With Si addition, the elongation, especially the uniform elongation at 350 ºC in LBE environment, improves, and the tendency toward crack propagation in T91 steel after slow tensile necking is reduced. The PLC phenomenon can be seen in both T91 and T91Si steels at high temperatures owing to the dynamic strain aging (DSA). The temperature ranges are different when DSA occurs, with 300–350 ºC and 250–350 ºC for T91 and T91Si steels, respectively.
Abstract：The tensile tests of T91 and T91Si steels at 200–450 oC in air and at 350 oC in oxygen-depleted liquid lead–bismuth eutectic (LBE) environment with strain rate of 1 9 10–5–5 9 10–3 were performed. Results show that the activation energy of T91 steel is 103.45–246.76 kJ/mol and that of T91Si steel is 146.98–172.11 kJ/mol when Portevin–Le Chatelie (PLC) phenomenon occurs. The elongation reduction of T91 steel at 350 oC is not specific to LBE environment, whereas the presence of LBE promotes crack initiation and propagation and affects the elongation of the material in the necking stage. With Si addition, the elongation, especially the uniform elongation at 350 oC in LBE environment, improves, and the tendency toward crack propagation in T91 steel after slow tensile necking is reduced. The PLC phenomenon can be seen in both T91 and T91Si steels at high temperatures owing to the dynamic strain aging (DSA). The temperature ranges are different when DSA occurs, with 300–350 oC and 250–350 oC for T91 and T91Si steels, respectively.
Ji Li,Xi-kou He,Gang Yang, et al. Effect of silicon on ductility of T91 steel in liquid lead–bismuth eutectic environment[J]. Journal of Iron and Steel Research International, 2023, 30(02): 363-374.
2023, Vol. 30 
