High-throughput Construction of Uranium Alloy Phase Diagram

Fa Tao¹*, Zhang Lei¹, Mo Wenlin¹, Xia Yuanhua², Zhang Changsheng², Zhou Peng³, Du Yong³, Bai Bin¹, Liu Kezhao¹, Wang Xiaolin¹,

¹Institute of Materials, China Academy of Engineering Physics, Jiangyou 621907, China

²Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621999, China

³State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083

ABSTRACT: Uranium element is widely used in nuclear industry because of its radioactivity, high density and good metallic properties. Alloying is the main method to improve the properties of uranium materials and obtaining an accurate phase diagram is one of the important parts of alloy design. A large amount of research work on the phase diagram and thermodynamic properties of uranium alloy materials was completed in the United States, the former Soviet Union, etc. between the 1950s to 1980s. There is still very little research work in basic theories and experiments on the phase equilibrium of uranium alloy materials in China, and there is still a big gap compared with the United States and Russia. Therefore, the construction of uranium alloy phase diagrams has important scientific significance. Due to its radioactivity, the experiment cost of uranium material is relatively high and the research period is long. Therefore, using the idea of material genetic engineering, we adopted high-throughput preparation and high-throughput characterization methods, and efficiently carried out experimental research on uranium alloy phase diagrams to accelerate the construction of uranium alloy multi-element phase diagrams. Through neutron high-temperature in-situ diffraction experiment, a series of key temperatures and phase regions in the U-Nb phase diagram were determined, which successfully solved the disputes existing between the US and the USSR phase diagram and established the U-Nb phase diagram with independent intellectual property rights. Compared with the traditional phase diagram experiment, the research efficiency of neutron high-temperature in-situ diffraction has been improved by orders of magnitude. The U-Nb-Zr-Ti diffusion multiples were prepared, and the high-throughput characterization of the composition and structure of the U-Nb-Zr diffusion multiples was realized by synchrotron radiation. The composition and structure of hundreds of micro-regions were obtained in just one experiment, which greatly improved the experimental efficiency of the multi-phase diagrams. Combined with thermodynamic calculation, the U-Nb-Zr ternary alloy phase diagram was constructed efficiently.

Keywords: uranium alloy; phase diagram; neutron diffraction; synchrotron radiation.