航空学报 > 2025, Vol. 46 Issue (12): 431401-431401   doi: 10.7527/S1000-6893.2024.31401

应力控制下织构对AZ31B疲劳性能的影响

程容湘1, 段国升1(), 张月盈1, 魏贺雨1, 武保林2   

  1. 1.沈阳航空航天大学 安全工程学院,沈阳 110136
    2.沈阳航空航天大学 材料科学与工程学院,沈阳 110136
  • 收稿日期:2024-10-15 修回日期:2024-11-08 接受日期:2025-01-07 出版日期:2025-02-06 发布日期:2025-01-16
  • 通讯作者: 段国升 E-mail:duanguosheng@sau.edu.cn
  • 基金资助:
    国家自然科学基金(51901140)

Effect of texture on fatigue properties of AZ31B under stress-controlled conditions

Rongxiang CHENG1, Guosheng DUAN1(), Yueying ZHANG1, Heyu WEI1, Baolin WU2   

  1. 1.School of Safety Engineering,Shenyang Aerospace University,Shenyang 110136,China
    2.School of Materials Science and Engineering,Shenyang Aerospace University,Shenyang 110136,China
  • Received:2024-10-15 Revised:2024-11-08 Accepted:2025-01-07 Online:2025-02-06 Published:2025-01-16
  • Contact: Guosheng DUAN E-mail:duanguosheng@sau.edu.cn
  • Supported by:
    National Natural Science Foundation of China(51901140)

摘要:

挤压镁合金作为结构件在航空航天领域已有了较为广泛的应用。织构对镁合金在应用过程中的安全可靠存在明显的影响。在不同的应力加载方向下,具有{0001}基面织构特征的样品其循环变形机制、棘轮应变以及疲劳寿命都有显著的差别。分别在平行于挤压方向(ED)和垂直于挤压方向(TD)制备了两种织构特征的样品,选取在不同应力水平下进行对比实验。结果表明:织构对挤压镁合金的循环变形过程和疲劳寿命有显著影响。在循环初期ED样品主导变形机制为孪生机制,而TD样品则以位错滑移为主,导致ED产生的棘轮应变大。随着循环的进行,无论ED还是TD样品的主要变形机制均转化为位错变形机制,残余孪晶对位错的阻碍作用导致ED样品显现出相对TD样品更明显的循环硬化。TD样品c-轴在TD面上随机分布决定了TD样品相对于ED样品可启动的位错和孪生机制更多。因此,TD样品相较ED样品表现出更大的棘轮应变、塑性应变幅以及塑性应变能密度,最终导致较短的疲劳寿命。

关键词: 应力控制, 织构, 棘轮, 变形机制, 疲劳寿命

Abstract:

Extruded magnesium alloys have been widely used as structural components in aerospace industry, within which the texture has a significant effect on the safety and reliability of magnesium alloys in the process of application. Under stress-controlled cyclic loading conditions, the {0001} basal texture has a significant effect on the deformation mechanism, ratcheting strain and fatigue life during cyclic deformation.Samples with two kinds of textures were prepared parallel to the Extrusion Direction (ED) and Perpendicular to the Extrusion Direction (TD), respectively, and selected for comparative experiments at different stress levels. The results show that the texture has a significant effect on the cyclic deformation process and fatigue process of extruded magnesium alloys. At the early stage of cycling, the dominant deformation mechanism of ED samples is twinning mechanism, while the TD samples are dominated by dislocation slip, and the ratcheting strain generated in ED is large. As the cycling progresses, the dominant deformation mechanism of both ED and TD samples is transformed into dislocation deformation mechanism, and the hindering effect of residual twins on dislocations leads to more pronounced cyclic hardening in ED samples relative to TD samples. The random distribution for c-axis of TD samples on the TD surface determines that more dislocations and twins can be initiated in TD samples relative to ED samples. As a result, the TD samples exhibit greater ratchet strain, plastic strain amplitude, and plastic strain energy density compared to the ED samples which ultimately leads to shorter fatigue life.

Key words: stress-controlled, texture, ratchet, deformation mechanism, fatigue life

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