• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2024, Vol. 60 ›› Issue (20): 99-107.doi: 10.3901/JME.2024.20.099

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Effect of Different Heat Treatments on Microstructure and Tensile Properties of TC4 Titanium Alloy Fabricated by Laser Directed Energy Deposition

RONG Peng1, Cheng Jing1, DENG Hongwen2, TAO Changan2, GAO Chuanyun1, RAN Xianzhe2, CHENG Xu2, TANG Haibo2,3, LIU Dong2,3   

  1. 1. AVIC Chengdu Aircraft Industry (Group) Co., Ltd., Chengdu 610092;
    2. National Engineering Laboratory of Additive Manufacturing for Large Metallic Components, Beihang University, Beijing 100191;
    3. Beijing Yuding Additive Manufacturing Research Institute Co., Ltd., Beijing 100096
  • Received:2023-09-06 Revised:2024-04-17 Online:2024-10-20 Published:2024-11-30

Abstract: Laser directed energy deposition (DED) is a manufacturing technology for producing high performance fully dense near-net metallic components, which is melting metal powders point by point and stacking them layer by layer. Since the microstructure of DEDed TC4 titanium alloy is different from that made by traditional forging, selecting appropriate heat treatment process can improve its mechanical properties significantly. The effects of three different heat treatment on microstructure morphologies and tensile properties of DEDed TC4 alloy were investigated. The results show that after 600 ℃ and 800 ℃ annealing treatment, the α lamellae coarsens to different degrees, and the volume fraction of α phase increases slightly. The double annealing heat treatment at 975 ℃ results in the appearance of equiaxed α phase, improving room-temperature plasticity with about 26.1% higher in average transverse reduction of area than that after 800 ℃ annealing treatment. After double annealing heat treatment at 975 ℃, TC4 alloy has the highest transverse average elongation at high temperature tensile test at 400℃, showing excellent high temperature strength-plastic balance.

Key words: additive manufacturing, laser directed energy deposition, Ti-6Al-4V, microstructure, room-temperature property, high-temperature behavior

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