Investigation of microstructure and liquid lead corrosion behavior of a Fe-18Ni-16Cr-4Al base alumina-forming austenitic stainless steel

The microstructure of an alumina-forming austenitic stainless steel with a composition design of Fe-18Ni-16Cr-4Al-2Mo-0.4 Nb (in wt%) is characterized. The steel contains about 75 vol% austenitic phase and 25 vol% ferritic phase. B2-NiAl precipitates with round shape can be found only in the ferritic phase in the as-rolled sample. The corrosion behavior in static liquid lead with different oxygen content of 10−9 and 10−6% by mass at 700 °C for 1000 h is investigated. After exposure for 1000 h in liquid lead with oxygen content of 10−9%, obvious lead penetration combined with nickel dissolution is found. In the case of liquid lead with 10−6% oxygen content, a thin oxide layer can be formed on the surface, thus protecting the steel from liquid lead attack. After the corrosion test, significant precipitations are found in both austenitic and ferritic phases in the matrix of the steel

Study on the Chemical Compatibility Study Between Li2TiO3 Pebbles and 14Cr-ODS Steel

In order to investigate the chemical compatibility between tritium breeder Li2TiO3 pebbles and tritium breeder blanket material oxide dispersion strengthened (ODS) steel, the contact interface between Li2TiO3 pebbles and ODS steel heated in argon atmosphere at 500, 600 and 700 degrees C for 300 h was studied. It was found that the ions of pebbles could diffuse and corrode with the cladding material after a long-time reaction at high temperature. The corrosion area formed on the surface of Li2TiO3 pebbles was small. With the increase of temperature, a zone with enriched iron was found on the surface of the pebble. This part of the surface was the direct contact surface between the pebble and the steel. At the same time, the relative density of the pebbles increased and the crush load was decreased to 30 N. In addition, a slight corrosion phenomenon was found on the surface of ODS steel. It has been proved that the main components of the corrosion products were the complex oxide containing Fe and Cr and the complex oxide containing Li and Fe.</p

W-Cu composites with homogenous Cu-network structure prepared by spark plasma sintering using core-shell powders

W-Cu composites with homogenous Cu-network structure were fabricated by spark plasma sintering using core-shell powders. The core-shell powders were obtained by intermittently electroplating method which can deposit shell composed of nano-copper on the core of micron tungsten particles. These nano-copper shells provide a large amount of grain boundaries, which are benefit for removing pores and improving the densification during sintering. Thus, the W-Cu composites can be obtained at low sintering temperature. The thermal conductivity, hardness and bending strength of the sintered W-Cu composites were investigated. The W-Cu composites show homogeneous microstructure and high thermal conductivity due to the formed fine Cu-network structure, low W-W contiguity and nearly full density