High-Temperature Steam Oxidation Behavior of VDM Alloy 699 XA Produced by Laser Powder Bed Fusion

Abstract VDM alloy (AM) 699 XA (AM-XA) produced by laser powder bed fusion (LPBF) was subjected to steam oxidation at different high temperatures. Initial studies on mass gain of AM-XA at 650 °C after 500 hours revealed insignificant changes. Typical to high temperatures, a wide range of oxides were obtained at 750 and 950 °C associated with mass gain. To fully understand AM-XA material behavior at high temperatures, hot-rolled 699 XA (HR-XA) was also fabricated and tested under similar conditions. At 750 °C, HR-XA showed a higher mass gain in comparison with AM-XA, whereas at 950 °C mass gain of AM-XA overtook HR-XA. This anomalous behavior was related mostly to carbide formation. In-depth anomalous behavior of AM-XA is explained by investigating the microstructure and phase composition of the oxidation products formed.