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  • Vol. 54  期 10， 2024 2024年 54卷 第10期

    • “Huaguang”Cup Excellent Thesis Recommendation

      PAN Yanfei,WANG Lin,XU Jian,LI Zhongshu

      DOI：10.7512/j.issn.1001-2303.2024.10.01
      摘要：This article investigated the effects of different heat treatment regimes on the microstructure and mechanical properties of Ti-6Al-4V alloy fabricated by laser arc composite additive manufacturing. The changes in microstructure under different heat treatment parameters were analyzed using optical microscopy and scanning electron microscopy, and the reasons for the changes in mechanical properties of the samples under different solid solution temperatures and cooling rates were explored. The results showed that the microstructure of Ti-6Al-4V alloy fabricated by laser arc composite additive was mainly composed of Widmanstein Flat noodles structure and a small amount of acicular α phase in columnar β grain extending outward from the substrate along the deposition direction. After solution aging heat treatment, the microstructure was mainly a typical interlaced basket structure, the thickness of Flat noodles was significantly reduced, and the plasticity and toughness of the sample were significantly improved. When the solution aging heat treatment scheme was 950 ℃/1 h, AC+540 ℃/6 h, AC, compared with the deposited sample, the grain size was reduced by 2 times and better comprehensive mechanical properties could be obtained. It was recommended to adopt this heat treatment scheme.  
      关键词：composite additive manufacturing;Ti-6Al-4V alloy;heat treatment;microstructure;mechanical property   
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      更新时间：2024-10-12

    • LIU Pan,SUN Huawei,QIN Jian,YANG Zijia,LIU Sheng,LIU Yonghua,WANG Wei,TAO Wang,ZHOU Litao

      DOI：10.7512/j.issn.1001-2303.2024.10.02
      摘要：In order to improve the surface wear resistance of titanium alloy materials, TC4 (Ti-6Al-4V) was selected as the matrix material in this paper. A certain proportion of diamond and graphite particles were added to TiZrCuNi brazing material to make a composite coating material. The diamond composite brazing coating on TC4 was achieved by induction brazing under argon protection. The effect of graphite addition on the microstructure and wear resistance of composite coatings was studied, revealing the interaction mechanism between the active element Ti and diamond and graphite. The research results indicate that after adding graphite, the composite coating is mainly composed of diamond, TiC, Ti2Cu, ZrC, Zr2Cu, NiZr2, and residual graphite. Due to the presence of a large number of helical dislocations in graphite, it provides nucleation sites for TiC, allowing it to grow along the dislocations, thus evolving the growth mode of TiC into enveloping growth and ultimately forming a hexagonal shape. The addition of graphite weakens the wear resistance of the composite coating to a certain extent, but can increase the cutting edge rate of diamond particles, thereby improving grinding efficiency.  
      关键词：TC4;diamond;brazing coating;graphite;wear resistance   
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      更新时间：2024-10-12

    • WANG Hongxiao,WANG Chunsheng,DENG Gang,ZHU Zongtao,CHEN Hui

      DOI：10.7512/j.issn.1001-2303.2024.10.03
      摘要：The study aims to investigate the fatigue crack growth behavior in different regions of a 12 mm thick TC4 titanium alloy laser-MIG hybrid welded joint and to analyze the interaction between microstructure and crack growth. Volume microscopy, phase microscopy, scanning electron microscopy, and electron backscatter diffraction (EBSD) techniques were used to explore the crack growth rates in different parts of the joint, the changes in crack growth paths, the interaction between microstructure and crack growth in different joint regions, and the deformation characteristics of the tissue around the crack tip. The results show that in the stable crack growth phase, the crack growth rate in the base metal area is the highest, which is 1.16 times and 1.81 times that of the heat-affected zone and the weld zone, respectively. When ΔK = 20 MPa·m1/2, the crack growth rate in the base metal is 3.39×10-4 mm/cycle. The IPF map at the crack tip indicates that the proportion of large-angle grain boundaries in the weld zone is 36.36%, which is higher than the 11.91% in the base metal and the 11.65% in the heat-affected zone. The presence of large-angle grain boundaries causes the crack to deflect along the grain boundaries or consume more energy to pass through the grain boundaries, increasing the crack growth resistance and showing better crack growth resistance. The base metal and heat-affected zone exhibit a mixed fracture mode of intergranular brittle fracture and ductile fracture, while the weld zone mainly shows a ductile fracture mode. In addition, EBSD analysis results show that the weld zone near the crack tip has a higher geometric dislocation density, and dislocations accumulate at the martensite boundary, causing the crack to deflect along the grain boundary, further hindering crack growth. Schmidt factor analysis also shows that the difference in orientation between the weld zone tissues is large, resulting in a higher crack growth threshold. In conclusion, the presence of a large number of large-angle grain boundaries and high dislocation density in the weld zone is the main reason for the higher crack growth resistance in the weld zone.  
      关键词：titanium alloy;fatigue crack growth;laser-MIG hybrid welding;fracture mode;crack tip;crack growth behavior   
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      更新时间：2024-10-12

    • JIA Fei,ZHAO Dan,CHENG Zhan,FAN Zhibin,NING Shaochen,LI Xiaoliang

      DOI：10.7512/j.issn.1001-2303.2024.10.04
      摘要：The aim of this paper is to study the influence of Ce-group rare earth elements on the solidification structure, solid solution structure, aging precipitation behavior, and properties of high-performance silicon white copper solder. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron probe microanalysis (EPMA) were used to observe the microstructure and test the properties of Cu-Ni-Si solders with different Ce contents. The results show that the addition of Ce-group rare earth elements significantly refines the solidification structure of the silicon white copper solder, reducing the grain size from 200 μm to 40 μm after addition. The addition of Ce elements inhibits the solid solution recrystallization process of the solder and refines the recrystallized grain size, increasing the recrystallization temperature from 900 ℃ to 950 ℃ and reducing the recrystallized grain size from 180 μm to 90 μm. The addition of Ce elements can promote the precipitation of Ni and Si elements and inhibit the growth of precipitated phases during the over-aging stage, but it does not change the type of aging precipitated phases, which are disk-shaped δ-Ni2Si and rod-shaped β-Ni3Si. The Cu-3.2Ni-0.75Si-0.06Ce silicon white copper solder achieves the best performance after aging at 450 ℃ for 4 h, with a tensile strength of 747 MPa and a shear strength of 454 MPa. Compared to the Cu-3.2Ni-0.75Si solder without Ce elements, the tensile strength is increased by 117 MPa, an increase of 18.6%, and the shear strength is increased by 91 MPa, an increase of 25%.  
      关键词：silicon white copper solder;Ce element;solution treatment;aging precipitation;tensile strength   
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      更新时间：2024-10-12
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    1. 0 1 Research Progress and Prospect of Wire and Arc Additive Manufacturing with Low Heat Input and High-efficiency Forming

      ZHANG Hanyan,XIONG Jun,CHEN Yong,CHEN Hui 1172 | 228 | 0

    2. 0 2 Research Progress of Additive Manufacturing Driven by Digital Twins

      DING Donghong,JI Jiang,ZHANG Zixuan,DING Xiaofei 1080 | 376 | 0

    3. 0 3 Research Progress of Trajectory and Process Planning in Wire Arc Additive Manufacturing

      ZHAO Tao,YAN Zhaoyang,JIANG Fan,CHEN Shujun 1014 | 184 | 0

    4. 0 4 Research Progress in Wire-Arc Additive Manufacturing of Magnesium Alloys

      CAO Qianhui,ZENG Caiyou,ZHANG Ruize,WANG Haibo,QI Bojin,CONG Baoqiang 978 | 165 | 0

    5. 0 5 Progress of Wire Arc Additive Manufacturing of Aluminum Alloys

      DONG Bolun,CAI Xiaoyu,XIA Yunhao,LIN Sanbao 971 | 245 | 0

    6. 0 6 Effect of Ultrasonic Impact Treatment on the Microstructure of Low Carbon Steel Fabricated by Wire and Arc Additive Manufacturing

      SUN Laibo,HUANG Ruisheng,WU Pengbo,XU Fujia,FANG Naiwen 857 | 133 | 0

    7. 0 7 Wire Arc Additive Manufacturing Technology and Application of Aluminum Alloy Lattice Structure

      ZHENG Bo,YU Shengfu,YU Runzhen,LI Yongjie,TANG Lun 849 | 163 | 0

    8. 0 8 Research Progress of Wire Arc Additive Manufacturing Technology for Aluminum Alloy

      FANG Xuewei,YANG Jiannan,CHEN Ruikai,HUANG Ke,LU Bingheng 793 | 363 | 0

    9. 0 9 Study on Forming Characteristics for Double-tungsten TIG Arc-based Additive Manufacturing

      HAN Qinglin,HE Ao,LI Xinlei,ZHANG Guangjun,LI Wenhang 744 | 158 | 0

    10. 10 Effect of Active Interpass Cooling on Temperature and Thermal Stress Evolution of Wire Arc Additively Manufactured Ti6Al4V Alloy

      ZHANG Yunshu,SHAO Dandan,DING Donghong,WU Bintao 611 | 179 | 0

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