Microstructure and Mechanical Properties of 2219 Aluminum Alloy Friction Stir Welded Blank after Cryogenic Deformation

doi:10.3901/JME.2025.14.091

Abstract

Abstract: Aluminum alloy friction stir welded blank is a new way to manufacture thin-walled components such as the bottom of the fuel tank of the launch vehicle over 3 meters in diameter, but it faces bottleneck problems such as deformation and abnormal growth of weld grain after heat treatment and degradation of mechanical properties. The microstructure and mechanical properties of 2219 aluminum alloy friction stir welded blank after ultra-low temperature deformation, solution treatment and aging treatment were studied. The average grain size of the weld and the mechanical properties of the joint after deformation and heat treatment at room temperature and cryogenic temperature were compared through uniaxial tensile test and deep drawing process, respectively. The results show that under the same deformation amount, the grain at the weld of the cryogenic deformed specimen is significantly refined. The average grain size of the weld decreased from 191 μm to 51.5 μm. The grain size of the weld in the biaxial tensile zone of the cryogenic deep drawing hemisphere was reduced by 61.9%, and the tensile strength of the transverse joint sample is 94.1% of the base metal. The cryogenic deformation can stabilize the grain boundaries, inhibit the abnormal growth of the grain in the weld zone, and improve the mechanical properties of the joints.

Key words: friction stir welded blanks, cryogenic deformation, abnormal grain growth, hemispherical deep drawing, mechanical property

CLC Number:

TG146

HAO Yonggang, JIN Xiaoyue, LIU Wei, WANG Ruiqian. Microstructure and Mechanical Properties of 2219 Aluminum Alloy Friction Stir Welded Blank after Cryogenic Deformation[J]. Journal of Mechanical Engineering, 2025, 61(14): 91-98.

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