The research scope is divided into three categories:alloy design, the relationships between composition, microstructure and properties, and the processing technology of engineering materials in nuclear power plants (NPPs). The main research and development plans include: (a) alloy design of austenitic and ferritic/martensitic steels with improved high-temperature strength, neutron-irradiation resistant and high-toughness for Gen IV nuclear power plants, (b) solidification behavior and the controlling mechanisms of minor and trace elements on segregation and precipitation during solidification, (c) microstructural evolution, the enhancement of microstructural homogeneity during hot or cold working and their effects on mechanical properties, irradiation behavior and corrosion performance, (d) the purification melting technology of special alloys. With the proceeding of fundamental research and processing technologies, a new ultra-purity melting route composed of Vacuum induction melting(VIM) plus Electroslag remelting(ESR) or Vacuum Arc remelting (VAR) is proposed to manufacture Inconel alloy 690, X12Cr12NiMo martensitic steels and Inconel 718 for Pressurized Water Reactors , and CN-1515 cladding for Fast Breeder Reactors.
The segregations of Cr, Ti, S, C, N in residual liquid of alloy 690 with different N contents after isothermal solidification at 1355℃
Grain size of alloy 690 with different N contents after solution annealing at 1080℃
Transversal and longitudinal macrostructures of Alloy 690 ESR ingot in 3.5t
External appearance and microstructure of Alloy 690 tube