金属热处理 ›› 2025, Vol. 50 ›› Issue (4): 134-142.DOI: 10.13251/j.issn.0254-6051.2025.04.019

• 组织与性能 • 上一篇    下一篇

反向等温挤压2024铝合金薄壁管的组织演化及增韧机理

李琦伦1,2, 张晓波1,2, 乔及森1,2   

  1. 1.兰州理工大学 材料科学与工程学院, 甘肃 兰州 730050;
    2.兰州理工大学 省部共建有色金属加工与再利用国家重点实验室, 甘肃 兰州 730050
  • 收稿日期:2024-11-11 修回日期:2025-02-18 发布日期:2025-06-13
  • 通讯作者: 乔及森,教授,博士,E-mail: qiaojisen@lut.edu.cn
  • 作者简介:李琦伦(1998—),男,博士研究生,主要研究方向为高强航空铝合金材料塑性成形及其强韧化,E-mail: 18215128251@163.com。
  • 基金资助:
    国家自然科学基金(52063017);甘肃省科技重大专项(20ZD7GJ008)

Microstructure evolution and toughening mechanisms of indirect isothermal extruded 2024 aluminum alloy thin-walled tube

Li Qilun1,2, Zhang Xiaobo1,2, Qiao Jisen1,2   

  1. 1. College of Materials Science and Technology, Lanzhou University of Technology, Lanzhou Gansu 730050, China;
    2. State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals, Lanzhou University of Technology, Lanzhou Gansu 730050, China
  • Received:2024-11-11 Revised:2025-02-18 Published:2025-06-13

摘要: 利用SEM及TEM表征手段对反向等温挤压2024铝合金薄壁管及其退火处理后的组织演变及强韧性机理进行了研究。结果表明,挤压过程,由于塑性变形诱导细小S(Al2CuMg)相沿挤压方向析出,同时保留均匀化态T(Al20Cu2Mn3)弥散相,T相兼具抑制再结晶和弥散强化双重作用,且产生高密度位错并形成亚晶结构,从而导致挤压态合金的抗拉强度增至304.73 MPa,断后伸长率达12.3%。退火处理后,S相部分粗化削弱析出强化作用,但位错缠结网络促进亚晶细化,并增强晶界钉扎效应,使塑性进一步提高(断后伸长率达15.7%)。同时,S相取向性减弱趋于等轴化,降低各向异性,使合金强度下降。

关键词: 2024铝合金, 反向等温挤压, 组织演化, 强韧性

Abstract: Microstructure evolution and strengthening and toughening mechanisms of 2024 aluminum alloy thin-walled tube subjected to indirect isothermal extrusion and after annealing treatment were studied by means of SEM and TEM characterization techniques. The results show that during the extrusion process, plastic deformation induces the precipitation of fine S(Al2CuMg) phase along the extrusion direction, while the homogenized state T(Al20Cu2Mn3) dispersed phase is retained, which plays a dual role of suppressing recrystallization and dispersion strengthening, and produces high-density dislocations and forms a subgrain structure. As a result, the tensile strength of the extruded alloy increases to 304.73 MPa, and the elongation after fracture reaches 12.3%. After the annealing treatment, the partial coarsening of the S phase weakens the precipitation strengthening effect. However, the dislocation entanglement network promotes the refinement of sub-grains and enhances the grain boundary pinning effect, further improving the plasticity (the elongation after fracture reaches 15.7%). At the same time, the orientation of the S phase weakens and tends to be equiaxed, reducing the anisotropy and resulting in a decrease in the strength of the alloy.

Key words: 2024 aluminum alloy, indirect isothermal extrusion, microstructure evolution, strength and toughness

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