Morphological Characteristic and Formation Mechanism of Joint of Meltspun Cu—Sn Alloy Foils By Capacitor Discharge Welding
ZHAI Qiuya; XU Jinfeng
School of Materials Science and Engineering; Xi'an University of Technology; Xi'an 710048
Cite this article:
ZHAI Qiuya; XU Jinfeng. Morphological Characteristic and Formation Mechanism of Joint of Meltspun Cu—Sn Alloy Foils By Capacitor Discharge Welding. Acta Metall Sin, 2005, 41(7): 755-758 .
Abstract The connection behavior and joint microstructure of capacitor
discharge welding for melt--spun Cu--20%Sn
alloy foils are investigated by using a
micro--type capacitor discharge
welding machine. The micro joint consists of
nugget zone, semi--melt zone and heat affect zone.
The rapid solidification microstructure characterized
mainly by fine b--Cu5.6Sn equiaxed grains are
produced in the nugget. The thickness of semi--melt zone is
only 2.0---3.0um and there is no obvious
change of microstructure in heat--affected zone.
Under the electrode pressure and
electromagnetic force, the liquid phase
flow occurs in undercooled nugget, which is symmetrical
about the electrode axis and connection interface and results
in the formation of curving streamline. The
porosity is the main welding defect produced
during welding. With the increase of electrode
pressure pm, the radius of porosity sharply decreases.
If the electrode pressure is more than 1.0 MPa,
this decrease tendency becomes smooth. The liquid phase
flow promotes the collision, coalescence and movement of bubbles,
resulting in that porosities distribute along the periphery of
nugget.
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