• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2024, Vol. 60 ›› Issue (18): 146-153.doi: 10.3901/JME.2024.18.146

• 材料科学与工程 • 上一篇    下一篇

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AA2024-T3铝合金搅拌摩擦沉积增材组织及性能

王瑞林, 杨新岐, 唐文珅, 罗庭   

  1. 天津大学材料科学与工程学院 天津 300354
  • 收稿日期:2023-09-17 修回日期:2023-12-28 出版日期:2024-09-20 发布日期:2024-11-15
  • 作者简介:王瑞林,男,1997年出生。主要研究方向为固相摩擦焊接与增材制造技术。E-mail:wangruilin9999@163.com
    杨新岐(通信作者),男,1962年出生,博士,教授,博士研究生导师。主要研究方向为固相摩擦焊接与增材制造技术、焊接结构疲劳断裂及完整性评定。E-mail:xqyang@tju.edu.cn
  • 基金资助:
    国家自然基金资助项目(52175356,51775371)。

Microstructure and Mechanical Properties of Additive Friction Stir Deposition for AA2024-T3 Alloy

WANG Ruilin, YANG Xinqi, TANG Wenshen, LUO Ting   

  1. School of Materials Science and Engineering, Tianjin University, Tianjin 300354
  • Received:2023-09-17 Revised:2023-12-28 Online:2024-09-20 Published:2024-11-15

摘要: 采用自主研制的固相摩擦挤压增材制造设备进行20层2024-T3铝合金搅拌摩擦沉积增材(Additive friction stir deposition, AFSD)试验,探讨沉积界面塑性流动及沉积累积热循环对其微观组织和力学性能的影响。结果表明:在主轴转速300 r/min、横向移动速度100 mm/min下可成功获得成形良好的20层增材试样,每层厚度约为2.5 mm,最终增材宽度和高度分别在50~52 mm和48~50 mm。带凸台打印工具的搅拌摩擦挤压作用,使得沉积界面处材料混合程度明显提高并消除原始界面连线痕迹,有效提升沉积层界面结合强度并避免弱连接和未连接等缺陷产生。增材整体具有细小等轴晶组织特征,增材试样的整体晶粒尺寸在2~3 μm。由于第二相粒子对晶界的钉扎作用,虽然增材层第1~12层区域受到多次热循环的影响,但其晶粒尺寸未发生长大。由于增材区的主要强化相溶解和粗化,硬度和抗拉强度在第1~12层发生明显降低。其中,第20层沉积层硬度最大为125 HV,第1-12层硬度均匀在70~80 HV。增材区水平方向第13~20层、第1~12层和垂直方向的平均抗拉强度为287.4 MPa、239.1 MPa和227.3 MPa;平均伸长率为14.3%、19.7%和17.7%。沿两个方向的断裂模式均为韧性断裂。

关键词: 搅拌摩擦沉积增材, 2024-T3铝合金, 微观组织, 力学性能

Abstract: The additive friction stir deposition experiment for AA2024-T3 alloy with deposited 20-layers was performed using independently developed solid-state friction extrusion additive manufacturing equipment, and the effects of interfacial plastic flow and multiple depositing thermal cycles during AFSD on the microstructure and mechanical properties of builds were investigated. It is shown that the well-formed build with 20-layer depositions is successfully obtained using the spindle rotational speed of 300rpm and transversal speed of 100 mm/min, each deposited layer is about 2.5 mm with thickness, and the width and height of the final build are measured to be in the range of 50-52 mm and 48-50 mm respectively. The friction stirring and squeezing actions of the print tool with protrusions greatly improve the interfacial mixing degree of material between the deposited layers and, obviously, remove the traces of original interfacial bond lines. The interfacial bonding strength of the deposited layers is increased and the weak bonding or lack of bonding defects is eliminated. The build has forged microstructure features with fine equiaxed grains, and the grain size of the 20-layer build is in the range of 2-3 μm. Due to the pinning effect of the second phase particles relative to the grain boundaries, the grain size of the additive layer does not grow, although the region of layers 1-12 is affected by multiple thermal cycles. A significant reduction in hardness and tensile strength occurs in layers 1-12 due to the dissolution and growth of the main reinforcing phase in the additive zone. Among them, the hardness of the deposited layer 20 is a maximum of 125 HV, and the hardness of layers 1-12 is uniformly in the range of 70-80 HV. The tensile strengths in the longitudinal direction(LD) layers 13-20, 1-12 and build direction (LD) directions in the reinforced zone are 287.4 MPa, 239.1 MPa and 227.3 MPa; the elongations are 14.3%, 19.7% and 17.7%. Fracture modes in both LD and BD directions are ductile fractures.

Key words: AFSD, AA2024-T351 alloy, microstructure features, mechanical property

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