Preferred orientation and microstructure evolution of Al3Ni Phase in the Al–18.at%Ni alloy during directional solidification under a high magnetic field

Mechanical deformation, heat treatment and solidification under magnetic field are common methods to control the preferred orientation of alloys.Among these methods, solidification under a magnetic field is a clean and effective emerging control method that has received widespread attention. Because of the widespread existence of anisotropy, the preferred orientation of alloys has a significant effect on their performance. Peritectic alloys are an important type of metallic material. The peritectic phase of the alloy is often attached to the primary phase for growth, and it forms a certain phase and orientation relationship with the primary phase. Therefore, the preferred orientation of the peritectic phase is closely related to the primary phase. Although there are many reports on peritectic alloys, there are few reports on the treatment of peritectic alloys with different tensile speeds under magnetic field, which is urgent to fill this research gap.

Recently, a team led by Professor Tie Liu of Northeastern University reported for the first time that the effects of high magnetic field and withdrawal speed on the preferred orientation and microstructure of peritectic alloys. The microstructural evolution of the mushy zone and solidification interface was characterized to reveal the mechanism of the magnetic field and pulling velocity effects. The relationship between the effects of the high magnetic field and pulling velocity on the preferred orientation of the peritectic alloy was also clarified.

The team published their work in Materials and Solidification on March 10, 2025.

“In the paper, Al and Ni particles with purity of 99.99% were used to prepare an Al–18 at.%Ni master alloy using a vacuum induction melting furnace. The master alloy ingot was cut into 6 mm diameter × 120 mm long cylindrical rods by wire cutting. We used the self-developed equipment under strong magnetic field to carry out directional solidification and quenching experiments. After the experiments, the microstructure morphology was observed by optical microscopy and scanning electron microscopy. The various phase components were identified by energy dispersive spectroscopy. The longitudinal section was prepared by argon ion etching for characterizing  the orientation behavior of the grains by electron back-scatter diffraction.” said Professor Tie Liu of Northeastern University, who is a senior professor of metal solidification. He has published more than 100 SCI papers in academic journals at home and abroad. The main research direction is metal solidification behavior and microstructure control under high magnetic field.

“In recent years, although there are many studies on peritectic alloys, there are few reports on the treatment of peritectic alloys at different tensile speeds under magnetic field. In view of the urgent need to carry out this research gap, we carried out this research and achieved certain results.” said Tie Liu.

“The high magnetic field significantly changed the directional solidification microstructure of the Al–18 at.%Ni alloy through TEMC and magnetic force. At low pulling velocities, owing to the magnetic force, hypereutectic reactions occurred instead of peritectic reactions at the front of the solidliquid interface. The effect of the TEMC and magnetic force became weaker with the pulling velocity increased.” said Tie Liu.

“The high magnetic field significantly changed the preferred orientation of the Al₃Ni phase. The magnetic field effect on the crystal orientation of an alloy during directional solidification is strongly dependent on the growth velocity.” said Tie Liu.

Other contributors include Sinuo Li and Wenzhao Liu from the School of Materials Science, Baoze Zhang, Xuefeng Yao, Xiaopeng Yin, and Xiaoyu Guo from the School of Metallurgy, all affiliated with Northeastern University in Liaoning Province, China, as well as Qiang Wang, Vice President of Northeastern University in Liaoning Province, China.

About Author

Professor Tie Liu is a Ph.D. Supervisor at Northeastern University, China, and holds key academic leadership roles, including Secretary-General of the Electromagnetic Metallurgy and High Magnetic Field Materials Science Branch under the Chinese Society for Metals, Council Member of the Foundry Branch of the Chinese Mechanical Engineering Society, and Council Member of the Solidification Science and Technology Branch of the Chinese Materials Research Society. He also serves on the editorial boards of Shanghai Metals and Foundry Technology. With a career dedicated to the frontier field of high magnetic field materials science, Professor Liu has established an interdisciplinary research team, "High Magnetic Field Materials and Metallurgical Processes," integrating materials science, metallurgy, and electromagnetic fluid mechanics. Under his leadership, the team developed an internationally recognized experimental platform for high magnetic field research, which underpinned the establishment of China’s sole Key Laboratory of Electromagnetic Processing of Materials (EPM) under the Ministry of Education, where he serves as Director of the High Magnetic Field Materials Science Division. These efforts have positioned China as a global leader in this field.

His research has been supported by over 20 major projects, including two National Natural Science Foundation of China (NSFC) General Programs, subprojects of NSFC Major and Major Research Instrument Development Programs, a National Key R&D Program subproject, a subproject of the MIIT Major Special Program, and key initiatives from the Ministry of Education and provincial governments. He has also contributed to collaborative national projects such as the 973 Program and NSFC initiatives. Recognized for excellence, his team was awarded the "National Innovation Research Group Cultivation Project" by the Central University Basic Research Fund, the "Innovation Team Support Program" by Liaoning Provincial Department of Education, and the "Xing Liao Ying Cai Program" Innovation Team title.

Professor Liu’s research spans high magnetic field experimental technologies, metal solidification mechanisms under extreme magnetic conditions, and advanced fabrication of high-performance metallic functional materials. His pioneering work includes the development of proprietary material preparation and characterization systems for extreme magnetic environments, the formulation of a theoretical framework for high magnetic field-induced metal solidification, and magnetic field-assisted functional material synthesis techniques, achieving innovation from fundamental research to industrial applications. His scholarly contributions comprise 150+ SCI-indexed papers, including three invited reviews for ISIJ International, 17 patented inventions (8 authorized), and 15 invited conference presentations (1 plenary, 5 keynote). He has authored one monograph, co-authored three books (including one international publication), and contributed to a textbook. His honors include the First Prize of Natural Science Award from the Ministry of Education, two Liaoning Provincial Natural Science Second Prizes, and a Rare Earth Science and Technology Second Prize. He also co-authored the strategic consultancy report Global Engineering Frontiers 2020 for the Chinese Academy of Engineering, further demonstrating his impact on shaping research priorities in materials science and engineering.

About Materials and Solidification

Materials and Solidification is a single-blind peer-reviewed, fully open access international journal published by Tsinghua University Press, with academic support provided by the State Key Laboratory of Solidification Processing, Northwestern Polytechnical University. The Journal aims to publish cutting-edge research results in solidification theory and solidification technologies for metal, semiconductor, organic, inorganic, and polymer materials in bulk or as thin films. It includes, but is not limited to, casting, welding, and additive manufacturing related to solidification processing, and is also involved in nonequilibrium solidification phenomena in multiphysical fields, such as electricity, ultrasonication, magnetism, and microgravity.