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Laser powder bed fusion of Al-Mg-Zn-Cu-Si-Sc-Zr alloy synergistically strengthened by Mg2Si, L12-Al3（Sc, Zr）, and η' multiple nano-particles

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Progress in Natural Science:materials International 2025年第2期 420-432页

作者： Chengzhe Yu Yangbo Wang Xiaoxing Yuan Nan Kang Linda Ke Changjian Jia Tiechui Yuan Ruidi Li State Key Laboratory of Powder Metallurgy Central South University Arts et Metiers Institute of Technology MSMP HESAM Université Shanghai Engineering Technology Research Center for Near-net Forming of Metal Materials Shanghai Aerospace Precision Machinery Institute

During the additive manufacturing process,Al-Zn-Mg-Cu alloys are susceptible to cracking.A specific Al-6.2Mg-1.95Zn-0.6Cu-3Si-0.35Sc-0.15Zr-0.4Mn alloy was developed for laser powder bed fusion（LPBF） *** addition of Si,Sc,and Zr improved the printability of the Al-Mg-Zn-Cu *** excellent tensile strength of 600MPa and a ratio of yield stress to ultimate stress of 0.75 were *** as-printed sample showed bimodal microstructures with fine equiaxed grains at the molten pool boundary and coarse columnar grains within the melt pool along the vertical *** precipitates,including β-Mg2Si,L12-Al3（Sc,Zr）,and η' were observed,resulting in high-strength aluminum *** mechanism of segregation of Sc,Zn and other alloying elements was revealed by first-principles calculations,and the binding energy of Si-Sc atomic pairs was found to be as high as 0.093 eV/pair at the nearest neighbor *** TEM and DFT results revealed that the η'-Mg(Cu1.5Zn0.5) structure,formed by three Cu atoms co-substituting Zn atoms,exhibited the lowest formation energy and represented the most thermodynamically stable η' phase discussed in this *** study provided the theoretical foundation for composition modification and precipitation of Al-Zn-Mg-Cu fabricated through laser powder bed fusion（LPBF）.

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Stress Partitioning of the Phases and Microstructural Evolution in Cast Al-8.3zn-4.3mg-0.8mn Alloys with Different Fe Contents

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SSRN 2024年

作者： Chen, Jingsi Zhao, Yuliang Tang, Chuanyao Liu, Le-Hua Song, Dongfu Zhang, Weiwen National Engineering Research Centre of Near-net-shape Forming for Metallic Materials South China University of Technology Guangzhou510641 China School of Materials Science and Engineering Dongguan University of Technology Dongguan523808 China Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Institute of New Materials Guangdong Academy of Science Guangzhou510650 China

Recycled aluminum alloys typically contain various second phases, whose effects on mechanical properties are not clearly understood. This study utilized synchrotron radiation X-ray imaging and diffraction techniques, along with transmission electron microscope, to systematically investigate the microstructural evolution and the stress partitioning of different phases of Al-Zn-Mg alloys with varying Fe contents and strains. The results indicate that the primary Al6(Fe,Mn) appears, and the 3D morphology changes from Chinese script-like to interconnected lath-like structure as the Fe content increased from 0.1% to 1.0%. Simultaneously, the addition of Fe led to increased yield strength (YS) but decreased ductility. Deformation mechanism studies revealed that the increase of YS was caused by strong stress partitioning characteristic of Al6(Fe,Mn). When alloy fractured, Al6(Fe,Mn) phase bears the stress about 827 MPa, which is approximately 540 MPa higher than that of α-Al. However, the premature failure of the lath-like Al6(Fe,Mn) at the strain of 1% was the main cause of subsequent brittle fracture of the alloy, which had limited the potential increase in YS from higher volume fractions of Al6(Fe,Mn) phases. This work not only provides new insights into the deformation mechanisms of aluminum alloys with high Fe content but also offers new ideas for the design of microstructures and composition in recycled alloys. © 2024, The Authors. All rights reserved.

关键词： Aluminum alloys

Investigation on dissimilar bonding and feasibility of binder-assisted microfluidic chip

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Engineering Plastics Application 2024年第1期52卷 77-83页

作者： Li, Shutong Liu, Po Huang, Jijie Han, Pengbiao Hebei Key Laboratory of Near-Net Forming Technology of Materials College of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China Guilin University of Aerospace Technology School of Mechanical Engineering Guilin541004 China

Polymethyl methacrylate (PMMA), polystyrene (PS) and aluminum alloy Al5052 were used as the research objects. The orthogonal experiments of PMMA-PS and PMMA-Al5052 dissimilar bonding were carried out by combining binder and hot pressing bonding. The purpose of this study is to investigate the variation of the thickness and apparent morphology of the bonding layer, and to study the effects of bonding temperature, pressure and time on the strength of dissimilar bonding. The results show that the thickness of the bonding layer decreases with the increase of temperature and pressure, while the time has no obvious effect on the thickness of the bonding layer. The bonding strength of polyimide (PI) assisted PMMA-PS and PMMA-Al5052 is most affected by time, followed by temperature and pressure. The bonding strength of PMMA-Al5052 assisted by acetone solution (PMMA) is most affected by pressure, followed by temperature and time. The bonding strength of PMMA-PS is much higher than that of PMMA-Al5052 under the same parameters. The optimal parameters of dissimilar bonding were established and the corresponding bonding strength was obtained. The optimal parameters of PI assisted PMMA-PS bonding are 105 ℃, 50 min, 2.5 MPa, and the corresponding bonding strength is 0.87 MPa. The optimal parameters of PI assisted PMMA-Al5052bonding are 110 ℃, 50 min, 1.25 MPa, and the corresponding bonding strength is 0.21 MPa. The optimal parameters of PMMA-Al5052 bonding assisted by acetone solution (PMMA) are 110 ℃, 2.5 MPa, 20 min, and the corresponding bonding strength is 0.41 MPa, which are higher than all the results in the orthogonal experimental design scheme. When the parameters are constant, the bonding strength of PMMA-PS is much higher than that of PMMA-Al5052. The bonding strength of PMMA-Al5052 assisted by acetone solution (PMMA) is higher than that assisted by PI. © 2024 Engineering Plastics Application Magazine. All rights reserved.

关键词： Plastics applications

Nucleation and Growth Mechanisms of Ferrite on Mg-Ti-Oxides Surface: First-Principles Investigation

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SSRN 2023年

作者： Liu, Er-Kang Wang, Qi Guo, Zhi-Hong Wang, Li-Jun Chang, Xi-Wang Zheng, Ya-Xu Ma, Chenyu Chen, Zhen-Ye Wang, Bo Zhu, Li-Guang Hebei Key Laboratory of Materials Near-Net Forming Technology School of Materials Science and Engineering Hebei University of Science and Technology Shijiazhuang050018 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing100083 China Institute of Energy and Power Innovation North China Electric Power University Beijing102206 China HBIS Material Technology Research Institute Shijiazhuang050000 China

Fine and dispersed Mg-Ti-oxide inclusions, which act as heterogeneous nucleation sites for intragranular ferrite, have been acknowledged as an effective method for grain refinement. In this paper, the nucleation and growth mechanisms of ferrite on Mg-Ti-oxides surface were investigated through first-principles calculations and solid-state pressure bonding experiments. The calculated results show that the formation of cation vacancies is the limiting step for Mn solute atom absorption by Mg-Ti-oxides. As determined by the lower covalency and ionicity of the Mg-O bond compared to the Ti-O bond in Mg-Ti-oxides, Mn atoms will be efficiently absorbed by occupying the Mg vacancies. The experimental results demonstrate that MgTiO3 with the maximum Mn-depleted zone (MDZ) width is the most effective for ferrite nucleation, which is consistent with the calculation results. As a representative, the Fe(110)/MgTiO3(001) interface with the lowest planar disregistry (3.16%) was selected to analyze growth behaviors. Due to charge accumulation and variation, Fe atoms are more likely to gather on the Mg-O terminal MgTiO3(001) surface and form [(Mg-O)-Fe]-1 interfaces. Its adhesion work and interface energy are 1.74 and 2.46 J/m2, respectively. The present study illustrates the nucleation and growth mechanisms of ferrite on Mg-Ti-oxides, providing theoretical support for the application of Mg-Ti-oxide inclusions in oxide metallurgy. © 2023, The Authors. All rights reserved.

关键词： Ferrite

Effects Of Applied Pressure And Residual Heat Quenching on the Mechanical and Thermal Properties of Al-Mg-Zn-Mn-Fe Alloys

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SSRN 2023年

作者： Chen, Jingsi Zhang, Weiwen Zhao, Yuliang Song, Dongfu Wang, Zhi Luo, Zongqiang Guangdong Key Laboratory for Processing Forming of Advanced Metallic Materials South China University of Technology Guangzhou510640 China School of Mechanical and Automotive Engineering South China University of Technology Guangzhou510640 China School of Mechanical Engineering Dongguan University of Technology Dongguan523808 China Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Institute of New Materials Guangdong Academy of Sciences Guangzhou510650 China National Engineering Research Centre of Near-net-shape Forming for Metallic Materials China

In this study, the effects of applied pressure (AP) and residual heat quenching (RQ) on the mechanical properties and thermal conductivities of Al-4.6Mg-3.6Zn-0.86Mn-0.48Fe alloys were investigated based on intensively microstructure analysis by scanning electron microscope (SEM), high resolution transmission electron microscopy (HRTEM) and synchrotron X-ray tomography (SXT). The results indicated that AP and RQ did not change the type of intermetallic;instead, they reduced the length and quantity of lath-like Al6(Fe,Mn), which was prone to crack formation during the tensile process. Moreover, η' precipitation particles were enriched at grain boundaries, which was beneficial for the yield strength of the alloy;the AP+RQ sample exhibited the best mechanical properties of the ultimate tensile strength, yield strength and elongation of 269 MPa, 164 MPa and 11.4%, respectively, which were 19%, 17%, and 83.8% higher than those of the gravity cast (GC) sample. Moreover, the thermal conductivity of the AP+RQ sample did not show significant changes, which were attributed to the reduction in solid solute caused by the increased volume fraction of η' precipitates, thus improving the thermal conductivity;however, the formation of numerous coherent interfaces between η' and the matrix led to increased lattice distortion, resulting in electron scattering. © 2023, The Authors. All rights reserved.

关键词： Aluminum alloys

Revealing the Macroscale Texture in an Additive Manufactured Co-Cr-Mo Alloy by Neutron Diffraction

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SSRN 2023年

作者： Tang, Shengyang Luzin, Vladimir Yang, Chao Zhang, Weiwen Wang, Zhi Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou510640 China National Engineering Research Center of Near-net-shape Forming for Metallic Materials South China University of Technology Guangzhou510640 China Lucas HeightsNSW2234 Australia School of Engineering The University of Newcastle CallaghanNSW2308 Australia College of Materials Science and Engineering

We firstly revealed the texture from macroscale of an additive manufactured Co-Cr-Mo alloy, which was produced by laser-based powder bed fusion (PBF-L) using a hatch rotation of 72° between the layers. The results show that the texture observed from the local area (microscale) was superposed. Furthermore, the overall bulk texture (macroscale) is not a simple algebraical sum of individual layers. The Goss texture component was observed in bulk. Instead of 5-fold symmetry texture in bulk, the texture is orthorhombic/tetragonal symmetry. Since this phenomenon occurs due to the manufacturing parameters, which shows the potential that the texture of PBF-L alloys can be tuned for optimizing the microstructure and properties. © 2023, The Authors. All rights reserved.

关键词： Chromium alloys

The Unexpected Low Fracture Toughness of Dual-Phase Steels Caused by Ferrite/Martensite Interface Decohesion

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SSRN 2024年

作者： Liu, Lang Li, Liejun He, Jiazhen Liang, Zhiyuan Peng, Zhengwu Gao, Jixiang Luo, Zhichao Huang, Mingxin National Engineering Research Center of Near-net Shape Forming Technology for Metallic Materials South China University of Technology Guangzhou510640 China Institute of New Materials Guangdong Academy of Sciences Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application Guangzhou510650 China Songshan Lake Materials Laboratory Dongguan523808 China Department of Mechanical Engineering The University of Hong Kong Pokfulam Road Hong Kong Guangdong Polytechnic Normal University Guangzhou510635 China

Recently, new categories of dual-phase (DP) steels with ultimate tensile strength (UTS) up to 1400 MPa have been developed by increasing martensite fraction and refining microstructure. The present work demonstrates for the first time that the fracture toughness of DP steel can be less than half of that of the counterpart fully martensitic steel with the same chemical composition. The severe decohesion of the ferrite/martensite (F/M) interface under high stress-triaxiality conditions is responsible for the unexpected large loss of fracture toughness in ultra-high strength DP steels. Furthermore, the DP steel with a martensite fraction (Vm) of 75% exhibits the lowest fracture toughness due to the continuity of F/M interfaces. © 2024, The Authors. All rights reserved.

关键词： Fracture toughness

Effect of Brazing Temperature on Microstructure And Shear Strength of Tial/Ti3al Joint Vacuum Brazed with Tih2-24ni Powder Filler

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SSRN 2024年

作者： Li, Li Wu, Bingzhong Zhang, Haowen Shen, Yuzun Zhang, Wentao Jiang, Yuqiang Li, Xiaoqiang School of Materials Science & Engineering East China Jiaotong University Nanchang330013 China State Key Laboratory of Performance Monitoring and Protecting of Rail Transit Infrastructure East China Jiaotong University Nanchang330013 China National Engineering Research Center of Near-net-shape Forming for Metallic Materials South China University of Technology Guangzhou510640 China

TiH2-24Ni (at.%) powder filler was innovatively designed and prepared by mechanical milling to vacuum braze TiAl-based and Ti3Al-based alloys at brazing temperatures of 1060 ~ 1120 ℃ for 10 min. The interfacial microstructure and formation mechanism of TiAl/Ti3Al brazed joints as well as the relationships among brazing temperature, microstructure and joint strength were systematically investigated. Results show that the TiAl/Ti3Al brazed joints are mainly composed of four interfacial reaction layers: TiAl alloy/γ-TiAl + α2-Ti3Al (layer Ⅰ)/α2-Ti3Al (layer Ⅱ)/α2-Ti3Al + α-Ti + δ-Ti2Ni (layer Ⅲ)/α2-Ti3Al + B2 (layer Ⅳ)/Ti3Al alloy. The hard δ-Ti2Ni gradually decreases and refines while the distribution of the low-hardness α-Ti is obviously homogenized with brazing temperature, but those in the joint brazed at 1120 ℃ are reversed. The shear strength of the TiAl/Ti3Al brazed joint first increases and then decreases with brazing temperature, and the maximum shear strength of 335 MPa is obtained at 1100 ℃. The cracks tend to initiate and propagate along the hard blocky δ-Ti2Ni in layer Ⅲ while the fracture surfaces show typical quasi-cleavage fracture characteristics. © 2024, The Authors. All rights reserved.

关键词： Shear strength

Efficient N-P Type Charge Compensatory Synergistic Effect for Hydrogen Production from Water Splitting: Theoretical Design of V/Nb-Re Co-Doping (X=S, Se)2 Photocatalyst

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SSRN 2023年

作者： Zhou, Zhonghao Li, Zhi Wang, Changfeng Key Laboratory of Near Net Forming of Light Metals of Liaoning Province Dalian Jiaotong University Dalian116028 China Engineering Research Center of Continuous Extrusion Ministry of Education Dalian Jiaotong University Dalian116028 China School of Materials and Metallurgy University of Science and Technology Liaoning Anshan114051 China

Photocatalytic hydrogen evolution reaction (HER) is a very promising method to solve the current environmental and energy crisis. Photocatalysts represented by two-dimensional (2D) transition metal dichalcogenides (TMDCs) have received extensive attention in this field, and methods such as doping have been developed to further improve their photocatalytic efficiency. However, the photocatalytic efficiency is limited by the fact that the photogenerated carriers in the single doping system are easy to recombine at the impurity levels. How to design the crystal structures of 2D TMDCs that can efficiently split water for hydrogen evolution is an important problem to solve the photocatalytic efficiency. Here, we designed the crystal structures of MoX(X=S, Se)2 co-doped with V/Nb and Re atoms by means of density functional theory (DFT). By N-P type co-doping, we found that this charge compensation effect indeed eliminates the impurity levels introduced by single atom doping, not only expanding the visible light response range, but also matching the thermodynamic conditions of photocatalytic water splitting, exhibiting excellent HER performance. The successful design of V/Nb-Re co-doped MoX(X=S, Se)2 crystal structure is a key step for the application of 2D TMDCs based photocatalyst in the field of practical photocatalysis. © 2023, The Authors. All rights reserved.

关键词： Density functional theory