The oxidation behavior of specimens containing tungsten inert gas welds of UNS NO6025
(NiCrFeAlY) was investigated in air for up to 5,000h at 900"-1000°C and 1,000h at 1100"-1200°C. In
general, the microstructure was very homogeneous in the weld with smaller carbides and the A203
intemal oxidation penetrations were similar or smaller compared to those formed in the base metal.
Oxidation rates are low for NO6025 in this temperature range compared to other commercial chromiaforming
alloys. As is typical for most alloys above 1000°C, scale spallation becomes more significant
and leads to depletion of A1 and Cr in the metal substrate beneath the oxide. The depletion was observed
to occur to a similar extent in both the weld and base metal for N06025. The maximum intemal oxidation
depth of the base metal at 900" and 1100°C was lower than several other commercial Ni-base alloys.