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1

Simulation and Heat Treatment Process of Carbon Nanotube Modified Aluminum Alloy (ZL105)

Zhang Zigi, Pan Zhilin, Li Rong, Zeng Qi, Liu Yong, Wu Quan

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

38--50

EN

To further improve the mechanical properties of carbon nanotubes (CNTs) modified aluminum alloy (ZL105), the first principle was used to build the atomic structure of the alloy system and the alloy system was simulated by the VASP. After that, the heat treatment process of the cast aluminium alloy material with CNTs to enhance the alloy performance by the orthogonal experiment. The results of the research show that: (1) The energy status of the alloy system could be changed by adding the C atoms, but it did not affect the formation and structural stability of the alloy system, and the strong bond compounds formed by C atoms with other elements inside the solid solution structure can significantly affect the material properties. (2) The time of solid solution has the greatest influence on the performance of material that was modified by CNTs. The solution temperature and aging temperature were lower strength affection, and the aging time is the lowest affection. This paper provides a new research method of combining the atomic simulation with the casting experiment, which can provide the theoretical calculations to reduce the experiment times for the casting materials’ performance improvement.

2

Influence of Asymmetrical Bending Pipe with Different Gating Systems on Low-Pressure Metal Mold Casting

Wang Ning, Li Rong, Zhang ZiQi, Zeng Qi

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

83--102

EN

To prepare a high-quality asymmetrical bending pipe of aluminum alloy by casting, the parting surfaces of the asymmetrical parts were determined based on the characteristics of the parts. Also, the forming process was designed and calculated. After that, the different types of gating systems were designed and the casting process was calculated by ProCAST, and then the influence of different casting gating systems on asymmetrical bending pipes was analyzed. The simulation results show that in the solidification process, although the filling speed of the single runner was slow, but the filling was stable. The gating system with a single runner-round flange filling system would lead to being more uniform for filling flow field and be sequential solidification of temperature field distribution, and stronger of the feeding ability. During the solidification process, the solid phase ratio of the single runner-round flange casting system is larger, and the shrinkage volume is smaller, which made the quality of castings better. Finally, a metal mold and core were made to cast a perfect asymmetric bending pipe of aluminum alloy product in a die casting machine. So the single runner-round flange filling system is suitable for asymmetrical bending pipe casting.

3

Influence of the Interface of Carbon Nanotube-Reinforced Aluminum Matrix Composites on the Mechanical Properties – a Review

Li Rong, Pan Zhilin, Zeng Qi, Xiaoli Ye

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

23--36

EN

Carbon nanotubes (CNTs) are a good reinforcement for metal matrix composite materials; they can significantly improve the mechanical, wear-resistant, and heat-resistant properties of the materials. Due to the differences in the atomic structure and surface energy between CNTs and aluminum-based materials, the bonding interface effect that occurs when nanoscale CNTs are added to the aluminum alloy system as a reinforcement becomes more pronounced, and the bonding interface is important for the material mechanical performance. Firstly, a comparative analysis of the interface connection methods of four CNT-reinforced aluminum matrix composites is provided, and the combination mechanisms of various interface connection methods are explained. Secondly, the influence of several factors, including the preparation method and process as well as the state of the material, on the material bonding interface during the composite preparation process is analyzed. Furthermore, it is explained how the state of the bonding interface can be optimized by adopting appropriate technical and technological means. Through the study of the interface of CNT-reinforced aluminum-based composite materials, the influence of the interface on the overall performance of the composite material is determined, which provides directions and ideas for the preparation of future high-performance CNT-reinforced aluminum-based composite materials.

4

Optimization of Al-Cu Cast Alloy Composition for Hydraulic Valves

Li Rong, Chen Lunjun, Zeng Qi, Su Ming, Xie Zhiping

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 1

84--94

EN

In order to identify the influence of different Mn, Cd, V and Zr content on the properties of Al-Cu casting alloys in hydraulic valves, orthogonal test methods were used to prepare alloy test bars with different elements and contents. Tensile tests were performed on the test bars so obtained. The microstructure of alloys with different compositions is studied. The results show that adding approximately 0.4% of Mn can not only form a strengthening phase but also reduce the excessive segregation of the matrix along the grain boundary. A Cd content of 0.2% can promote the formation of micro Cd spheres in the softer aluminum matrix. Hard spots increase the wear resistance of the material; however, an excess of Cd will cause element segregation and deteriorate the mechanical properties of the valve body. Zr and V refine the grains in the alloy; however, an excess of these elements will lead to a large area of segregation. If proper heat treatment is lacking, the mechanical properties of the valve body deteriorate.