The effect of pulse laser welding parameters and filler metal on microstructure and
mechanical properties of the new heat-treatable, wieldable, cryogenic Al-4.7Mg-0.32Mn-0.21Sc-0.1Zr
alloy were investigated. The optimum parameters of pulsed laser welding were found. They were
330–340 V in voltage, 0.2–0.25 mm in pulse overlap with 12 ms duration, and 2 mm/s speed and
ramp-down pulse shape. Pulsed laser welding without and with Al-5Mg filler metal led to the
formation of duplex (columnar and fine grains) as-cast structures with hot cracks and gas porosity
as defects in the weld zone. Using Al-5Ti-1B filler metal for welding led to the formation of the fine
grain structure with an average grain size of 4 ± 0.2 µm and without any weld defects. The average
concentration of Mg is 2.8%; Mn, 0.2%; Zr, 0.1%; Sc, 0.15%; and Ti, 2.1% were formed in the weld.
The ultimate tensile strength (UTS) of the welded alloy with AlTiB was 260 MPa, which was equal to
the base metal in the as-cast condition. The UTS was increased by 60 MPa after annealing at 370 ◦C
for 6 h that was 85% of UTS of the base alloy |
