Pb-Bi eutectic alloy has been receiving increasing attention as a heavy liquid metal coolant in accelerator driven systems and Generation IV fission reactors. Compatibility of structural materials with liquid PbBi eut...Pb-Bi eutectic alloy has been receiving increasing attention as a heavy liquid metal coolant in accelerator driven systems and Generation IV fission reactors. Compatibility of structural materials with liquid PbBi eutectic alloy at high temperature is one of the issues concerned. In the present study, corrosion tests of T91 steel in stagnant Pb-Bi eutectic alloy in saturated oxygen condition at 450 oC were carried out. After experiments, the thickness and compositional profile of the oxide layer on the specimen were analyzed using SEM and EDX. Analysis results show that the thickness of the oxide layer increases as the exposure time increases from 500 h to 1,000 h. The thickness of the oxide layer remains almost unchanged at 15 to 16 mm from 1,000 to 1,500 h. Formation of a thick and protective oxide layer at 450 oC prevents the penetration of liquid Pb-Bi eutectic alloy into the matrix of the T91 steel.展开更多
Oxidation behaviors of blank and CeO2 coated T91 steel were investigated at 600 ℃ in water vapor for up to 150 h. Gold marker was used to define the mass transport direction. The oxide scales were studied with X-ray ...Oxidation behaviors of blank and CeO2 coated T91 steel were investigated at 600 ℃ in water vapor for up to 150 h. Gold marker was used to define the mass transport direction. The oxide scales were studied with X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electron probe microanalyzer （EPMA）. The oxidation resistance of the steel is improved by CeO2 coating, though the improvement is not remarkable. Ce-rich oxide band is located at the interface of the inner equiaxed layer and the outer columnar layer after oxidation, which is not consistent with the original surface. The results show that outward iron transport is blocked by the Ce-rich band. A new oxide nucleating and growing site （reaction front） is induced at the inner surface of the Ce rich band.展开更多
Microstructure performance in the welding zone of T91 heat-resistant steel under the condition of TIG welding was researched by means of metallography, X-ray diffraction and scanning electron microscope (SEM). Experim...Microstructure performance in the welding zone of T91 heat-resistant steel under the condition of TIG welding was researched by means of metallography, X-ray diffraction and scanning electron microscope (SEM). Experimental results indicated that microstructure of T91 weld metal was austenite + a little amount of S ferrite when using TGS-9cb filler wire. Substructure inside the austenite grain was crypto-crystal lath martensite, on which some Cr23C6 blocky carbides were distributed. The maximum hardness (HRC44) in the welding zone is near the fusion zone. There existed no obvious softening zone in the heat-affected zone (HAZ). For T91 steel tube of $63 mmx5 mm, when increasing welding heat input (E) from 4.8 kJ/cm to 12 5 kJ/cm, fracture morphology in the fusion zone and the HAZ changed from dimple fracture into quasi-cleavage fracture (QC). Controlling the welding heat input of about 9.8 kJ/cm is suitable in the welding of T91 heat-resistant steel.展开更多
Modified novel high silicon steel （MNHS, a newly developed reduced-activation martensitic alloy） and commercial alloy Tgl are implanted with 200 keV He2＋ ions to a dose of 5 × 1020 ions/m2 at 300, 450 and 560~...Modified novel high silicon steel （MNHS, a newly developed reduced-activation martensitic alloy） and commercial alloy Tgl are implanted with 200 keV He2＋ ions to a dose of 5 × 1020 ions/m2 at 300, 450 and 560~C. Transmission electron microscopy （TEM） is used to characterize the size and morphology of He bubbles. With the increase of the implantation temperature, TEM observations indicate that bubbles increase in size and the proportion of ＇brick shaped＇ cuboid bubbles increases while the proportion of polyhedral bubbles decreases in both the steel samples. For the samples implanted at the same temperature, the average size of He bubbles in MNHS is smaller than that in T91. This might be due to the abundance of boundaries and precipitates in MNHS, which provide additional sites for the trapping of He atoms, thus reduce the susceptibility of MNHS to He embrittlement.展开更多
基金financially supported by the Strategic Priority Research Program CAS under Grant No.XDA03010304the National Science Foundation of China under Grant No.91226204the Youth Innovation Promotion Association CAS
文摘Pb-Bi eutectic alloy has been receiving increasing attention as a heavy liquid metal coolant in accelerator driven systems and Generation IV fission reactors. Compatibility of structural materials with liquid PbBi eutectic alloy at high temperature is one of the issues concerned. In the present study, corrosion tests of T91 steel in stagnant Pb-Bi eutectic alloy in saturated oxygen condition at 450 oC were carried out. After experiments, the thickness and compositional profile of the oxide layer on the specimen were analyzed using SEM and EDX. Analysis results show that the thickness of the oxide layer increases as the exposure time increases from 500 h to 1,000 h. The thickness of the oxide layer remains almost unchanged at 15 to 16 mm from 1,000 to 1,500 h. Formation of a thick and protective oxide layer at 450 oC prevents the penetration of liquid Pb-Bi eutectic alloy into the matrix of the T91 steel.
基金Project(2007A-47) supported by Shandong Electric Power Corporation,China
文摘Oxidation behaviors of blank and CeO2 coated T91 steel were investigated at 600 ℃ in water vapor for up to 150 h. Gold marker was used to define the mass transport direction. The oxide scales were studied with X-ray diffractometry （XRD）, scanning electron microscopy （SEM） and electron probe microanalyzer （EPMA）. The oxidation resistance of the steel is improved by CeO2 coating, though the improvement is not remarkable. Ce-rich oxide band is located at the interface of the inner equiaxed layer and the outer columnar layer after oxidation, which is not consistent with the original surface. The results show that outward iron transport is blocked by the Ce-rich band. A new oxide nucleating and growing site （reaction front） is induced at the inner surface of the Ce rich band.
基金The work was supported by the Foundation of National Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, China.
文摘Microstructure performance in the welding zone of T91 heat-resistant steel under the condition of TIG welding was researched by means of metallography, X-ray diffraction and scanning electron microscope (SEM). Experimental results indicated that microstructure of T91 weld metal was austenite + a little amount of S ferrite when using TGS-9cb filler wire. Substructure inside the austenite grain was crypto-crystal lath martensite, on which some Cr23C6 blocky carbides were distributed. The maximum hardness (HRC44) in the welding zone is near the fusion zone. There existed no obvious softening zone in the heat-affected zone (HAZ). For T91 steel tube of $63 mmx5 mm, when increasing welding heat input (E) from 4.8 kJ/cm to 12 5 kJ/cm, fracture morphology in the fusion zone and the HAZ changed from dimple fracture into quasi-cleavage fracture (QC). Controlling the welding heat input of about 9.8 kJ/cm is suitable in the welding of T91 heat-resistant steel.
基金Supported by the National Basic Research Program of China under Grant Nos 2010CB832902 and 91026002the National Natural Science Foundation of China under Grant No U1232121
文摘Modified novel high silicon steel （MNHS, a newly developed reduced-activation martensitic alloy） and commercial alloy Tgl are implanted with 200 keV He2＋ ions to a dose of 5 × 1020 ions/m2 at 300, 450 and 560~C. Transmission electron microscopy （TEM） is used to characterize the size and morphology of He bubbles. With the increase of the implantation temperature, TEM observations indicate that bubbles increase in size and the proportion of ＇brick shaped＇ cuboid bubbles increases while the proportion of polyhedral bubbles decreases in both the steel samples. For the samples implanted at the same temperature, the average size of He bubbles in MNHS is smaller than that in T91. This might be due to the abundance of boundaries and precipitates in MNHS, which provide additional sites for the trapping of He atoms, thus reduce the susceptibility of MNHS to He embrittlement.
