Furnace brazing of AA5086 aluminum alloy with AISI 316L stainless steel by ER4047 and ER4043 fillers

Abstract EN

In this investigation AA5086-H116 aluminum alloys were furnace brazed with AISI316 stainless steel.

Brazing process was done with high purity nitrogen gas atmosphere.

ER4047 and ER4043 fillers were used with fillers thickness 80μm approximately.

Five holding times were employed (5, 10, 15, 20 and 25).

The microstructures examination showed two bounding layers.

First layer from stainless steel side with Fe-rich phases and second layer from aluminum side with Al-rich phase.

Joint strength was mainly depended on thickness of these two layers.

EDS results demonstrated high diffusion between fillers and two metals to form different intermetallic compounds and there is a clearly relationship between holding time and filler elements diffusion.

XRD indicated existing of Mg2Si and Al-Fe-Si phases at joining line and diffusion zone, which gives high strength.

When holding time raised more than 20 minutes brittle phases (Fe3Al, FeAl and FeAl3) would form or growth speedily in joining line and diffusion zone.

High hardness and brittle nature of these intermetallic phases will decrease mechanical properties of braziments.

Shear results recorded 18MPa for the AA5086-H116 joining with ER4047 for 20 minutes and 16Mpa when joining with ER4043 for 20 minutes also.