Acta Metallurgica Sinica (English Letters) ›› 2020, Vol. 33 ›› Issue (10): 1397-1406.DOI: 10.1007/s40195-020-01066-4

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Microstructure Evolutions and Properties of Al-Cu Alloy Joint in the Pulsed Power Ultrasonic-Assisted GMAW

Chao Chen1, Chenglei Fan1(), Zeng Liu1, Xiaoyu Cai1, Sanbao Lin1, Yimin Zhuo1   

  1. 1State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin, 150001, China
  • Revised:2020-03-14 Online:2020-10-10 Published:2020-10-20
  • Contact: Chenglei Fan

Abstract:

The pulsed power ultrasonic-assisted gas metal arc welding (PU-GMAW) is a new development hybrid welding method. The influences of the pulsed power ultrasonic on the microstructure evolution of the welded joint of Al-Cu alloy were investigated by using scanning electron microscopy, transmission electron microscope and electron back scattering diffraction. The results showed that the efficient heat input in the PU-GMAW was increased by above 100% compared with the traditional GMAW. The grain and eutectic of the PU-GMAW weld seam were refined compared with that of the GMAW. Cavitation and acoustic streaming induced the dendrite fragmentation (α-Al) and heterogeneous nucleation, which were the main reasons for the grain refinement. The microhardness of the PU-GMAW welded joint was improved compared with that of the GMAW owing to the change of the eutectic and grain.

Key words: Pulsed power ultrasonic, Al-Cu alloy, Microstructure, Cavitation, Acoustic streaming