Basic research on and the industrial development of zirconium alloys in China started relatively late, with insufficient domestic production capacity for zirconium alloy castings; especially for large-sized zirconium alloy castings, there is little production experience and significant challenges in quality control. Therefore, the production and research and development of zirconium alloy castings have received widespread attention from academia and industrial production sectors. This article analyzes the production status of domestic zirconium alloy castings, examines the casting process characteristics of valve body castings, and optimizes the casting process based on ProCAST simulation analysis results, using a lost foam precision casting process to cast a large-sized, high-pressure zirconium alloy casting for chemical use. The phase composition and microstructure were tested and analyzed, and the results showed the following: there is a certain thickness of the diffusion contamination layer on the surface of the castings. Finally, key points regarding zirconium alloy casting surface quality control and welding quality control were proposed, effectively improving the quality of the castings.

With the rapid development of the nuclear power industry, the requirement for nuclear structural materials is continuously growing. Eu-Ni intermetallic alloys are promising structural candidates for nuclear applications, while relevant fundamental investigations and underlying mechanisms remain insufficient worldwide. In this work, four Eu-Ni alloys with Eu mass fractions from 30 wt.% to 75 wt.% were fabricated via vacuum electromagnetic levitation melting. Thermodynamic calculations were performed to analyze high-temperature evaporation behaviors of Eu and Ni, and desired compositions were accurately achieved by evaporation loss compensation. XRD, SEM-EDS, TEM-SAED and hardness measurements were used to characterize phase constituents, microstructure and mechanical properties. The maximum evaporation rates of Eu and Ni increase with rising respective elemental contents. As Eu content increases, the dominant phase evolves from hexagonal EuNi5 to EuNi2 and finally FCC Eu-rich Eu0.56Ni0.44. The average grain size decreases from 127.82 μm to 67.59 μm, and intergranular spacing increases from 9.09 μm to 17.72 μm. Grain-boundary segregation of Eu softens the matrix, leading to a gradual hardness reduction from 529.2 kg/mm² to 247.4 kg/mm². This study clarifies composition-dependent evolution rules and provides fundamental data for industrial preparation and nuclear application of Eu-Ni alloys.